GIFT  OF 


• 


THE 

COMPLETE 

Practical    Machinist : 

EMBRACING 

LATHE  WORK,  VISE  WORK, 

DRILLS   AND   DRILLING,  TAPS  AND    DIES, 

HARDENING  AND  TEMPERING, 

THE  MAKING  AND  USE  OF  TOOLS, 

TOOL  GRINDING,  MARKING  OUT  ¥ORK,  ETC. 


BY 

JOSHUA    ROSE 


Illustrate!*  ifi  8Hjm  $un&n&  anJr  F( 


FIFTE  $$7  V '  FDITIOA^  -   \ 
THOROUGHLY  REUSED  ANDJft  CRE^T.PART  REWRITTEN. 


PHILADELPHIA . 
HENRY  CAREY  BAIRD  &  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS, 
810  WALNUT  STREET. 

LONDON: 

SAMPSON  LOW,  MARSTON,  SEARLE  &  RIVINGTON, 
CROWN  BUILDINGS,  188  FI.KKT  STIIKET. 

1887. 


Copyright,  JOSHUA  ROSE,  1885. 


COLLINS,  I'KINT-KR 


PREFACE  TO  THE  THIRTEENTH  EDITION. 


IN  presenting  to  machinists  a  thoroughly  revised 
edition  of  this  book,  the  author  would  be  ungrateful 
did  he  omit  to  express  his  sincere  thanks  for  the  unusual 
welcome  which  it  has  met  at  the  hands  of  American 
machinists,  and  also  for  the  large  number  of  kindly 
letters  of  appreciation  from  the  many,  on  both  sides  of 
the  Atlantic,  with  whom  he  has  become  acquainted 
through  the  medium  of  it. 

This  revision  brings  the  work  thoroughly  up  to  date, 
while  maintaining  its  chief  characteristic  of  being  as 
intelligible  to  the  student  and  apprentice  as  it  is  to  the 
skilful  machinist. 

JOSHUA  ROSE. 

NEW  YORK  CITY,  January  1,  1885. 
P.  O.  Box  3306. 


(13) 


251004 


CONTENTS. 


CHAPTER  I. 

CUTTING  TOOLS  FOR  LATHES  AND  PLANING  MACHINES. 

Importance  of  the  Lathe  ;  Steel  of  which  Cutting  Tools 
for  Lathes,  Planing  Machines,  etc.,  are  made  ; 

Classification  of  Lathe-cutting  Tools 25 

Classification  of  Slide-rest  Tools ;  The  Forming  of 
Cutting  Tools  ;  Illustration  of  the  manner  in  which 
a  Lathe  Tool  cuts  the  Metal ;  Principal  considera- 
tion in  determining  the  proper  shape  of  a  Cutting 

Tool 26 

Strain  upon  a  Tool 29 

Hake  in  Tools  3ft 

Principles  determining  the  proper  form  of  the  cutting 

edge  of  a  Tool 33 

Bound-Nosed  Tools 36 

Square-Nosed  Tools 37 

Angles  at  which  Tools  become   Cutters  or  Scrapers 

respectively  39 

Effect  of  the  diameter  of  the  work  and  the  rate  of  tool 
feed  on  the  amount  of  clearance  by  the  bottoir  rake 
or  side  rake  of  a  Tool ;  Bearing  of  the  height  of  the 
cutting  edge  of  a  Tool,  with  relation  to  the  work, 

on  its  cutting  qualities 40 

Practice  of  Sir  Joseph  Whitworth ;  Positions  in  which 

all  Tools  should  be  held 41 

Cutting  off  Parting  or  Grooving  Tools 44 

(15) 


16  CONTENTS. 

Side  Tools  for  Iron 47 

Front  Tool- for  Brass  Work 50 

Side  Tool  for  Brass  Work 53 

Special  Forms  of  Lathe  Tools 54 

Tool  Holders 55 

Woodbridge's  patent  Tools  and  Tool  Holder 57 


CHAPTER  II. 

CUTTING  SPEED  AND  FEED. 

Meaning  of  the  terms  "  Cutting  Speed  "  and  "  Feed  " , 
Planing  Machines  ;  Great  importance  of  "  Feed  " 
and  "  Speed  »  in  Lathe  Work 64 

44  Feed  "  and  "  Speed  "  for  various  kinds  of  work 65 

Tables  of  Cutting  Speeds  and  Feeds  ;  Tables  for  Steel ; 
for  Wrought-iron 69 

For  Cast-iron  ;  for  Brass ;  for  Copper ;  Speeds  where  the 
cuts  are  unusually  long  ones 70 

CHAPTER  III. 
BORING  TOOLS  FOR  LATHE  WORK. 

Standard  Bits  and  Reamers ;  The  Shaping  of  Boring 

Tools  for  Lathe  Work 71 

Pressure  on  the  cutting  edge  of  a  Tool,  with  Illustra- 
tion of  the  same 72 

Effect  of  the  Application  of  the  Top  Bake  or  Lip  to  a 

Boring  Tool 74 

Shape  for  the  corner  of  the  cutting  edge 75 

Illustrations  of  the  various  forms  of  Boring  Tools  for 

ordinary  use 76 

Boring  Tool  for  heavy  duty  on  Wrought-iron 77 

Boring  Tool  for  Brass 78 

Easing  a  piece  of  bored  Brass  or  Cast-iron  Work,  which 

fits  too  tight,  with  a  half  round  Scraper 79 

Boring  Tools,  with  Illustrations. 80 

Boring  Tool  Holders 82 


CONTENTS.  17 

CHAPTER  IV. 

SCREW-CtTTTING  TOOLS. 

Cutting  Surfaces  of  Lathe  Tools  for  cutting  Screws; 

Cutting  the  Pitch  of  a  Screw  which  is  very  coarse. .     84 
The  most  accurate  method  of  cutting  small  V  Threads.     85 
Tool  for  cutting  an  outside  V  Thread ;  Stout  Tool  for 
cutting  coarse  square  Threads  on  Wrought-iron  or 

Steel   86 

Single  pointed  Tool  for  cutting  an  internal  Thread; 
The  three  diiferent   shapes  of  V  Threads  in  the 
United   States— the  sharp  V  Thread,  the  United 
States  Standard,  and  the  "Whit worth  Thread  .....     87 
Comparative  ease  in  producing  these  several  Threads  .     88 
Gauges  for  testing  the  angles  of  Threading  Tools ;  Meas- 
uring the  Diameter  with  the  Calipers 90 

Testing  the  Pitch  of  a  Thread 91 

Centre  Gauge  and  Gauge  for  grinding  and  setting  Screw 

Tools 92 

Experiments  upon  Targets  representing  ship's  armor 
in  which  the  bolts  were  found  unable  to  resist  the 
shock,  and  the  remedy  for  the  defect ;  To  calculate 
the  change  Gear  "Wheels  necessary  to  cut  a  given 

Pitch  of  Thread  in  a  Lathe 94 

A  simple  or  single-geared  Screw-cutting  Lathe 95 

Compound  or  double-geared  Screw-cutting  Lathe 97 

Rule  by  which  to  find  the  number  of  Teeth  in  the 

Wheels  to  be  placed  on  the  Feed  Screw 98 

Compound  Gears  common  in  small  American  Lathes. . .  100 
Pitches  of  Threads  used  in  France,  and  the  method  of 
finding  the  necessary  change  gears;  To  cut  a  Double 

Thread 102 

To  cut  a  Treble  Screw 103 

Hand  Chasing 104 

To  make  a  Chaser 107 

Chaser  used  on  Wrought-iron  ;  An  inside  Chaser 110 

Yiews  of  an  inside  Chaser  applied  to  a  piece  of  work. . .  Ill 

Uses  of  an  inside  Chaser ;  Cutting  inside  Threads 113 

General  directions  in  cutting  Threads 114 


18  CONTENTS. 

CHAPTER  V. 
LATHE  DOGS,  CARRIERS  OR  DRIVERS. 

The  Bent-tailed  Dog,  its  objectionable  feature,  and  how 

it  may  be  obviated ;  The  Clements  Driver 116 

Clamp  Dog  for  rectangular  or  other  work,  not  cylindrical 
at  the  driving  end  ;  Form  of  Driver  for  driving  Bolts ; 

Adjustable  Driver;  Wood-turners'  Spur  centre 119 

Screw  Chuck  for  short  wood  work ;  Mandrils  or  Arbors.  120 

Centring  Lathe  Work  ;  Centre-grinding  device 122 

The  quickest  method  of  centring  Lathe  Work 123 

Centring  Machine ;  A  centre-drilling  attachment  for 

Lathe  Work 124 

Combined  Drill  and  Countersink  for  centre  drilling; 
Combined  Drill  and  Countersink,  in  which  a  small 
Twist-Drill  is  let  into  the  Countersink  ;  Centre  drill- 
ing by  hand 125 

Work  requiring  to  be  run  very  true  ;  A  square  centre  ; 

To  recentre  work  that  has  already  been  turned. 126 

Roughing  out  work  which  requires  to  be  turned  at  both 

ends ;  Finishing  Lathe  Work 127 

Emery  Cloth  and  Paper 128 

Grinding  Clamps  for  finishing  work  to  gauge  diam- 
eters ;  Arbor  for  grinding  out  Bores 130 

Lathe  Chucks;  The  three  classes  of  Chucks;  Horton 
two  jawed  Chuck ;  Box  body  Chuck ;  Three  and 

four-jawed  Chucks  131 

The  Sweetland  Chuck 133 

Drill  Chuck  of  the  Russell  Tool  Co 134 

Chuck  Dogs 135 

CHAPTER  VI. 
TURNING  ECCENTRICS. 

Chucking  an  Eccentric  which  has  a  hub  or  boss  on  one 
side  only  of  its  bore 136 

Chucking  an  Eccentric  having  a  large  amount  of  throw 
upon  it  138 

Turning  Crank 140 


CONTENTS.  19 

To  Chuck  a  Crosshead 141 

Counterbalancing  work 143 

Boring  Links  or  Levers 144 

Turning  Pistons  and  Rods 145 

Piston  Rings 14ti 

Expanding  Chuck  for  holding  Piston  Rings  or  similar 
work 150 

CHAPTER  VII. 
HAND  TURNING. 

One  of  the  most  delicate  and  instructive  branches  of  the 

Machinist's  art 151 

Far  more  instructive  to  a  beginner  than  any  other 

branch  ;  Chucking 153 

Roughing  out ;  The  Graver 154 

Holding  the  Graver 156 

The  Heel  Tool 157 

Hand-turning — Brass  work 159 

Scrapers 160 

CHAPTER  VIII. 
DRILLING  IN  THE  LATHE. 

Work  in  which  the  Lathe  is  resorted  to  for  drilling 

purposes 164 

Half-round  Bits 166 

Bit  in  which  a  Segment  has  been  cut  out  to  admit  a 

Cutter 167 

Cutter  and  Bar  designed  for  piercing  holes  out  of  the 
solid  and  of  great  depth  ;  Flat  Drill  to  enlarge  and 

true  them  out 168 

Drill-holder 170 

Reamers , 171 

Method  of  Grinding  a  Reamer 172 

Importance  of  maintenance  of  the  Reamer  to  Standard 

Diameter 174 

Reamer  which  may  be  adjusted  to  size  by  moving  its 

teeth ;  Adjustable  Reamer  for  very  small  work 175 

Shell  Reamers .  176 


20  CONTEXTS. 

CHAPTER  IX. 
BORING  BARS. 

Importance  of  the  Boring  Bar ;  Smaller  sizes  of  Boring 

Bar  usually  simple  parallel  Mandrils 178 

Boring  Bar  Cutters  requiring  to  be  Adjustable 179 

No  Machine  using  a  Boring  Bar  should  be  allowed  to 

stop  while  the  finishing  cut  is  being  taken 180 

A  rude  form  of  Head : 181 

Position  which  Cutters  should  occupy  towards  the  head 

or  Body  of  the  Bar 183 

Small  Boring  Bars '. . .  189 

CHAPTER  X. 
SLOTTING  MACHINE  TOOLS. 

Two  Classes  of  Tools  used  in  Slotting  Machines 191 

Tool  for  cutting  a  Half-round  Groove,  holding  Bar  and 

Short  Tool 192 

Knife  Tool  for  heavy  work 193 

CHAPTER  XI. 
TWIST  DRILLS. 

The  Cutting  Edges  of  Brills,  with  various  examples —  197 

Testing  Drills 199 

The  Flat  Drill 201 

To  increase  the  Keenness  of  a  Flat  Drill;  Feeding 

Drills • 202 

The  Farmer  Lathe  Drill ;  Experiments  of  Wm.  Sellers 

&  Co.  with  a  Flat  Drill 204 

Drilling  Hard  Metals 205 

Slotting  or  Keyway  Drills 206 

Pin  Drills 211 

Countersink  Drills 212 

Cutters 214 


CONTENTS.  21 

CHAPTER  XII. 
TOOL  STEEL. 

Cutting  Tools  for  .all    machines   should   be  made  of 

hammered  Steel 219 

Forging  Tools 220 

Tool  hardening  and  tempering 222 

Hardening ;  To  harden  Springs 227 

Case-hardening  Wrought-iron 229 

The  wear  of  metal  surfaces  230 

Annealing  or  Softening 236 

Mixtures  of  Metals 237 

CHAPTER  XIII. 
TAPS  AND  DIES. 

Forging  of  Taps 238 

The  Nut  Tap 240 

Taps  having  taper  in  the  diameter  of  the  bottom  of  the 
Thread;  Proper  taper  for  Hand  and  Machine 

Taps 241 

Taps  having  Thread  on  the  small  end  of  the  Taper; 
Turning  the  plain  part  of  a  Tap ;  Taps  for  use  in 
holes  to  be  tapped  deeply  ;  Finishing  the  Threads  of 

a  Tap 242 

Flutes  of   small  Taps ;    United    States    Standard  for 

Threads,  adopted  by  the  Franklin  Institute 243 

English  or  Whitworth  Standard  ;  Hardening  Taps 244 

Taps  of  three  and  of  four  Flutes 246 

The  Whitworth,  the  Brown  &  Sharpe,  and  the  Pratt  & 
Whitney  Taps  ;  The  position  of  the  Square  with  re- 
lation to  the  cutting  edges  in  Hand  Taps 248 

Adjustable  Dies 250 

Dies  for  use  in  Hand  Stocks 251 

CHAPTER  XIV. 

VISE-WORK— TOOLS. 

Chisels ;  Flat  Chisels 256 


22  CONTENTS. 

The  Koimd-nosed  Chisel ;  The  Oil-groove  Chisel 262 

The  Diamond-point  Chisel  263 

The  Side  Chisel ;  Application  of  Chisels  ;  Calipers 264 

The  Square 267 

The  Scribing  Block 268 

Files  and  Filing  ;  Fitting  Files  to  their  handles  ;  Select- 
ing a  File ;  Half-round  Files 269 

Holding  Files 270 

Filing  out  Templates 272 

Scrapers  and  Scraping 280 

Vise  Clamps  281 

Vise-Work—  Pening 282 

Fitting  Brasses  to  their  boxes 284 

Fitting  Link  Motions 28  > 

Fitting  Cylinders 288 

Scraped  Surfaces  — 297 

To  make  a  Surface  Plate 301 

To  cut  hard  Saw  Blades ;  To  refit  leaky  Plugs  to  their 

Cocks 304 

Refitting  work  by  Shrinking  it , 308 

Steam  and  Water  Joints 313 

CHAPTER  XV. 
FITTING  CONNECTING  RODS. 

The  mode  of  proceeding  with  the  work 314 

To  get  the  length  of  a  Connecting  Rod ;  To  ascertain 
when  the  Crank  of  a  Horizontal  Engine  is  upon  its 

exact  dead  centre 319 

Fitting  a  Connecting  Rod 320 

The  Oil-Hole  of  a  Connecting  Rod ;  The  Brasses  or  Side 

Rod 322 

Drifts ;  Smooth  and  toothed  or  cutting  Drifts 325 

Reverse  Keys ,329 

Setting  Line-shafting  in  Line 331 

CHAPTER  XVI. 
MILLING-MACHINES  AND  MILLING-TOOLS. 

Importance  of  the  Milling-machine. . . : 338 

Cutting  out  a  Corrugated  Surface  339 


CONTENTS.  23 

Advantage  of  Milling-tools  ;  To  Mill  the  Side  Faces  of 

a  Rod  with  Milling-bar  and  Cutters  340 

Examples  of  work  with  the  Milling-machine 341 

The  Side  Faces  of  the  Cutters 343 

Use  of  Milling-tools  for  cutting  the  Thread  on  Taps; 

Making  the  Milling-cutters . . .- 344 

Finishing  the   Cutter  in  the  Lathe  with  an  Emery 

Wheel 3?5 

The  Teeth  of  long  Cutters 346 

CHAPTER  XVII, 
GRINDSTONE  AND  TOOL  GRINDING. 

Uses  of  Grindstones;  Various  kinds  of  Grindstones; 
Dry  Grinding 347 

Qualities  of  different  Grindstones  ;  Treatment  of  Grind- 
stones    348 

To  make  a  Grindstone  run  true  ;  Accurate  Grinding ; 
Truing  up  a  Grindstone  for  Tool  Grinding 349 

Objections  to  the  intermittent  truing  of  a  Grindstone  ; 
Device  for  keeping  a  Grindstone  continuously  true  350 

Face  of  a  Grindstone  for  Flat  Surfaces  ;  Positions  for 
holding  Tools  in  Grinding 352 

A  Feather  Edge  on  a  Tool 353 

A  Device  called  a  Best  359 

CHAPTER  XVIII. 
LINING  OR  MARKING  OUT  WORK. 

Importance  of  Lining  Out  Work 360 

Principles  involved  in  Marking  Out  Work ;  Qualities 

necessary  for  a  Marker  Out 361 

To  mark  an  Ellipse 363 

To  find  Points  through  which  the  Curve  of  an  Ellipse 

may  be  drawn  364 

Tools  employed  by  a  Marker  Out 365 

To  divide  a  straight  line  into  two  equal  parts  ;  To  di- 
vide a  straight  line  into  a  number  of  equidistant 

points S67 

Measuring  Work  to  be  Marked  Out ;  Practice  of  Mark- 
ins  Out..  369 


24  CONTENTS. 

To  Mark  Off  an  Engine  Guide  Bar 373 

Use  of  the  Compass  Calipers  in  Marking  Out  Work. .    .  376 
Philosophy  of  Marking  Out  Holes  in  a  certain  manner.  377 

Centrepunch  Marks 378 

To  Mark  Off  the  Distance  between  the  Centres  of  two 

Hubs  of  unequal  height 379 

Marking  Holes  at  a  right  angle 381 

To  Line  Out  a  Double  Eye 383 

Marking  Out  an  Eccentric 389 

Lining  Out  Connecting  Rods 396 

To  Mark  Off  Cylinder  Ports  and  Steam  Valves 406 

Valve  Seats 407 

To  Mark  Out  a  Cone  Pulley 408 

CHAPTER  XIX. 
To  CALCULATE  THE  SPEED  OF  WHEELS,  PULLEYS,  ETC. 

CHAPTER  XX. 
How  TO  SET  A  SLIDE  VALVE. 

Considerations  in  Setting  a  Slide  Valve 414 

Practical  Operations  in  Setting  a  Valve 415 

CHAPTER  XXI. 
PUMPS. 

Suction  Pumps 423 

Force  Pumps 425 

Piston  Pumps 426 

A  Plunger  Pump 427 

Efficiency  of  a  Pump,  how  increased 428 

Causes  of  loss  of  efficiency  in  Pumps 430 

INDEX..  .  433 


THE 

COMPLETE  PRACTICAL  MACHINIST. 


CHAPTER  I. 

CUTTING   TOOLS    FOR   LATHES   AND   PLANING    MACHINES. 

THE  lathe  is  the  most  important  of  all  metal-cutting 
machines,  or  machine  tools  as  they  are  termed,  not  only  he- 
cause  of  the  comparative  rapidity  of  its  action,  but  also  from 
the  wide  range  and  variety  of  operations  that  may  be  per- 
formed in  it.  He  who  is  an  expert  lathe  hand,  or  turner, 
will  find  but  little  difficulty  in  operating  any  other  metal- 
cutting  machine  tool,  because  the  methods  of  holding 
work  and  the  shapes  of  the  tools  for  other  metal-cutting 
machines  are  similar,  and  are  governed  by  the  samo 
principles  as  in  the  case  of  lathe  work  ;  hence,  in  this  book 
all  tools  that  are  used  in  the  lathe  will  be  discussed  under 
the  head  of  lathe  tools,  notwithstanding  that  they  may  be 
also  used  in  other  machines. 

Cutting  tools  for  lathes,  planing  machines,  etc.,  etc.,  are 
made  of  a  special  grade  of  cast-steel  known  as  tool  steel. 
The  tool  is  first  forged  to  shape,  and  then  hardened  by 
heating  it  to  a  red  heat  and  dipping  it  in  water. 

Lathe-cutting  tools  may  be  divided  into  two  principal 
classes,  viz.,  slide-rest  tools  and  hand  tools.  The  latter, 
however,  have  lost  their  former  importance,  because  even 
small  lathes  are  now  provided  with  means  to  traverse  the 
tools  to  the  cut. 

3  (25) 


26  COMPLETE  PRACTICAL  MACHINIST. 

Slide- rest  tools  may  be  subdivided  into  two  classes, 
those  for  inside  or  internal  work,  and  those  for  external 
or  outside  work.  They  are  designated  from  either  the 
nature  of  the  duty  they  perform,  or  from  some  character- 
istic peculiar  to  the  tool  itself.  Thus  a  side  tool  is  one 
that  cuts  upon  a  side  or  end  face  ;  a  front  tool  is  one  that 
cuts  in  front ;  a  spring  tool  is  one  that  admits  of  deflection 
or  spring,  and  so  on. 

In  forming  cutting  tools  it  will  be  found  that  a  very 
slight  variation  of  shape,  or  of  presentment  to  the  work, 
causes  appreciable  difference  in  its  cutting  capacity, 
whether  for  smoothness  or  in  taking  off  a  quantity  of 
metal.  Furthermore,  the  shape  of  the  tool  mr.st  not  only 
be  varied  for  different  kinds  of  metal,  but  also  for  extremo 
differen-ces  of  hardness  in  the  same  kind  of  metal,  moro 
notably  in  the  case  of  steel,  some  of  which  is  almost  as 
soft  as  wrought-iron,  while  the  finer  grades  are  exceedingly 
hard,  especially  when  cut  from  the  bar  and  not  annealed 
or  softened  by  being  brought  to  a  red  heat  and  left  to  cool 
slowly.  Cast-iron  also  is  sometimes  exceptionally  hard, 
requiring  a  special  shape  of  tool,  while  wrought-irou  and. 
brass  vary  but  very  little  in  their  degree  of  hardness. 

The  manner  in  which  a  lathe  tool  cuts  the  metal  from 
the  work  when  fed  along  it  is  shown  in  Fig.  1,  which  rep- 
resents a  tool  feeding  a  cut  along  a  piece  of  wrought-iron, 
and  it  will  be  seen  that  the  cutting  comes  off  in  a  spiral. 
The  diameter  and  the  openness  of  this  spiral  depend  en~ 
tirely  upon  the  shape  of  the  tool,  so  that  from  the  ap- 
pearance of  the  cutting  the  quality  of  the  tool  may  be 
judged. 

The  principles  which  govern  the  shape  of  tool  necessary 
to  cut  a  piece  of  metal  under  any  given  condition  are 
general  in  their  application  ;  so  that  when  these  conditions 
are  clearly  understood  it  becomes  a  comparatively  easy 
matter  to  shape  a  tool  suitable  for  them. 

The  principal  consideration  in  determining  the  proper 


CUTTING  TOOLS.  2Y 

shape  of  a  cutting  tool,  for  use  in  a  lathe  or  planer,  is 
where  it  shall  have  the  rake  necessary  to  make  it  keen 

Fig.  1. 


WORK 


TOOL 


enough  to  cut  well,  and  yet  be  kept  as  strong  as  possible  ; 
and  this  is  governed,  in  a  large  degree,  by  the  nature  of 
the  work  on  which  it  is  to  be  used.  It  is  always  desirable, 
circumstances  permitting,  to  place  nearly  all  the  rake  or 

Fig.  2. 


keenness  on  the  top  face  of  the  tool,  as  shown  in  Fig.  2, 
in  which  D  is  the  top  face,  and  B  the  bottom  one;  lines 
A  A  and  E  E  representing  the  level  of  the  top  and  bot- 


28 


COMPLETE  PRACTICAL  MACHINIST. 


torn  of  the  tool  steel,  and  C  a  line  at  a  right  angle  to  E, 
or  what  is  the  same  thing,  to  A.     The  tool  in  Fig.  3  cor- 

Fig.  3. 


responds  to  that  in  Fig.  2  so  far  as  its  cutting  qualifica- 
tions are  concerned,  there  being  merely  a  slight  difference 
in  the  forged  shape,  but  not  in  the  cutting  edges.  That 
shown  in  Fig.  3  is  called  a  "diamond  point,"  from  the 
diamond  shape  of  its  top  face,  while  that  in  Fig.  2  is 
called  a  "  front  tool;"  the  former  being  more  suitable  for 
small,  and  the  latter  for  large  work. 

Referring  now  to  the  top  face  a,  its  angle  or  rake  is  its 
incline  in  the  direction  of  the  arrow  in  Fig.  4.     In  (hose 


Fig.  4. 


(to  be  hereafter  specified)  in  which  top  rake  is,  from 
the  nature  of  the  work  to  be  cut,  impracticable,  it  must  be 
taken  off  and  the  tool  given  the  necessary  ke.enness  by 
increasing  the  rake  or  angle  of  the  bottom  or  side  faces  in 


LATHE  AND  MACHINE  TOOLS.  29 

the  direction  shown  in  Fig.  5,  in  which  letter  b  represents 
u  side  or  bottom  face  of  the  tool,  its  amount  of  rake  being 
denoted  by  its  angle  in  the  direction  of  the  arrow. 

Fig.  5. 


These  top  and  side  faces,  taken  one  in  conjunction  with 
the  other,  form  a  wedge,  and  all  machine  tools  are  nothing 
more  than  cutting  wedges,  the  duty  performed  by  the 
respective  faces  depending,  first,  upon  the  keenness  of 
the  general  outline  of  the  top  and  bottom  faces,  and 
secondly,  upon  the  position,  relative  to  the  work,  in  which 
the  tool  is  held  and  applied. 

The  strain  sustained  by  the  top  face  is  not  alone  that 
due  to  the  severing  of  the  metal,  but  that,  in  addition, 
which  is  exerted  to  break  or  curl  the  shaving,  which 
would,  if  not  obstructed  by  the  top  face,  come  off  in  a 
straight  line,  like  a  piece  of  cord  being  unrolled  from  a 
cylinder;  button  coming  into  contact  with  the  face  of  the 
tool  (immediately  after  it  has  left  the  cutting  edge),  it  is 
forced,  by  that  face,  out  of  the  straight  line  and  takes  cir- 
cular form  of  more  or  less  diameter  according  to  the 
amount  of  top  rake  possessed  by  the  tool.  The  direction  of 
the  whole  strain  upon  the  top  face  is  at  a  right  angle  to  it, 
as  denoted  in  Fig.  6  by  the  line  D,  d  being  the  work,  B 
the  tool,  and  C  the  shaving.  It  will  be  readily  perceived, 
then,  that  if  a  tool  possessing  so  much  top  rake  is  held  far 
out  from  the  tool  post  or  clamp,  or  is  slight  in  body,  any 
springing  of  the  body  of  the  tool,  arising  from  the  pressure 
due  to  the  cut,  will  cause  the  tool  point  to  take  a  deeper 
cut,  and  that  the  tendency  of  the  strain  upon  the  top  face 
is  to  draw  the  tool  deeper  into  its  cut.  A  plain  cut  (either 
$* 


30  COMPLETE  PRACTICAL  MACHINIST. 

inside  or  outside)  admits  of  the  use  of  a  maximum  of  top 
rake  and  of  a  minimum  of  bottom  rake  in  all  cases  when 
the  tool  is  not  liable  to  spring. 

Were  the  strain  upon  the  tool  equal  in  force  at  all  times 
during  the  cut,  the  spring  would  also  be  equal,  and  the 
cut,  therefore,  a  smooth  one ;  but  in  taking  a  first  cut,  there 
may  be,  and  usually  is,  more  metal  to  be  cut  off  the  work 
in  one  place  than  in  another;  besides  which  there  are 
inequalities  in  the  texture  of  the  metal,  so  that  when  the 
harder  parts  come  into  contact  with  the  tool,  it  springs 
more  and  cuts  deeper  than  it  does  when  cutting  the  softer 
parts,  and  therefore  leaves  the  face  of  the  work  uneven. 


Fig.  6. 


TOOL 


The  main  duty  performed  by  the  bottom  face  of  the  tool 
is  to  support  the  cutting  edge,  and  the  amount  of  rake  it 
possesses  is  not,  under  ordinary  circumstances,  of  very  great 
consequence,  so  that  it  be  sufficient  to  well  clear,  and  not 
rub  against  the  work.  It  is  always  desirable,  however,  to 
give  it  as  little  rake,  over  and  above  clearance,  as  possible, 
to  avoid  weakening  the  cutting  part  of  the  tool. 

When,  in  consequence  of  the  top  face  having  but  very 
little  rake,  it  becomes  necessary  to  make  the  general  out- 
line of  the  tool  keen  by  the  application  of  the  maximum 
of  side  or  bottom  rake,  the  tool  becomes  proportionately 
weak,  as  is  shown  in  Fig.  7;  in  which  a  represents  the 
work,  B  the  tool,  c  the  shaving,  and  D  the  direction  of 


LATHE  AND  MACHINE  TOOLS. 


31 


the  strain  placed  upon  the  top  face  of  the  shaving,  from 
which,  it  will  be  noted,  that  the  cutting  edge  is  compar- 
atively weak,  and  hence,  liable  to  break. 


Fig.  7. 


Fig.  8. 


It  follows,  then,  that  if  two  tools  are  placed  in  posi- 
tion to  take  an  equal  cut  off  similar  work,  that  which 
possesses  the  most  top  rake,  while  receiving  the  least  strain 
from  the  shaving,  receives  it  in  a  direction  the  most  likely 
to  spring  it  into  its  cut.  It  must  not,  therefore,  be  used 
upon  any  work  having  a  tendency  to  draw  the  tool  in,  nor 
upon  work  to  perform  which  the  tool  must  stand  far  out  from 
the  tool  post,  for  in  either  case  it  will  spring  into  its  cut. 

Especially  is  this  likely  to  occur  if  the  cut  has  a  break  in 
it  with  a  sharply  defined  edge,  such,  for  example,  as  turn- 
ing a  shaft  with  a  dovetailed  groove 
in  it.  Taking  all  these  considera- 
tions into  account,  we  arrive  at  the 
tool  shown  in  Fig.  8,  as  represent- 
ing the  most  desirable  amount  of 
top  and  bottom  rake  for  ordinary 
purposes  on  light  work  ;  such  a  tool 
is  not,  however,  adapted  to  taking 

very  heavy  cuts,  for  which  duty  the  top  face  of  the  tool  is 
given  what  is  termed  side  rake. 

Fig. 9  represents  a  tool  having  a  maximum  of  side  rake, 
and  therefore  designed  for  very  heavy  duty,  and  to  be  held 
as  close  to  the  tool  post  as  possible.  The  amount  of  power 
required  to  feed  a  lathe  or  other  tool  into  its  cut,  at  the 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  9. 


' 


same  time  that  the  tool  is  cutting,  is  considerable  when  a 
heavy  cut  is  being  taken ;  and  the  object  of  side  rake  is  not 
only  to  make  the  tool  more  keen  without  sacrificing  its 
strength,  but  to  relieve  the  feed  screw  or  gearing  of  part 
of  this  strain  by  giving  the  tool  a  tendency  to  feed  along 
and  into  its  cut,  which  is  accomplished  by  side  rake,  thus: 


Fig.  10. 


Suppose  Fig.  10  to  represent  a  tool  having  side  rake 
its  feed  being  to  the  left  and  the  pressure  of  ihe  shav- 
ing will  be  more  sideways.  It  has  in  fact  followed  the 


LATHE  AND  MACHINE  TOOLS.  33 

direction  of  the  rake,  decreasing  its  tendency  to  run,  or 
spring,  in  (as  shown  in  Fig.  6),  with  a  corresponding  gain 
in  the  above-mentioned  inclination  to  feed  itself  along,  Or 
into,  its  lateral  cut. 

When  side  rake  is  called  into  use,  a  corresponding 
amount  of  front  rake  must  be  dispensed  with,  or  its  ten- 
dency to  feed  itself  becomes  so  great  that  it  will  swing 
round,  using  the  tool  post  as  a  centre,  and  (feeding  rapidly 
into  the  cut)  spring  in  and  break  from  the  undue  pressure, 
particularly  if  the  lathe  or  machine  has  any  play  in  the 
slides.  So  much  side  rake  may  be  given  to  a  tool  that  it 
will  feed  itself  without  the  aid  of  any  feed  motion,  for  the 
force  required  to  bend  the  shaving  (in  heavy  cuts  only) 
will  react  upon  the  tool,  forcing  it  up  and  into  its  cut, 
while  the  amount  of  bottom  rake,  or  clearance  as  it  is 
sometimes  called,  may  be  made  just  sufficient  to  permit  the 
tool  to  enter  its  cut  to  the  required  thickness  of  shaving 
or  feed  and  no  more;  and  it  will,  after  the  cut  is  once 
begun,  feed  itself  and  stop  of  itself  when  the  cut  is  over. 
But  to  grind  a  tool  to  this  exactitude  is  too  delicate  an 
operation  for  ordinary  practice.  The  experiment  has,  how- 
ever, been  successfully  tried ;  but  it  was  found  necessary 
to  have  the  slides  of  the  lathe  very  nicely  adjusted,  and  to 
take  up  the  lost  motion  in  the  cross-feed  screw. 

For  roughing  out  and  for  long  continuous  cuts,  this 
tool  is  the  best  that  can  be  used  ;  because  it  presents  a 
keen  cutting  edge  to  the  metal,  and  the  cutting  edge  re- 
ceives the  maximum  of  support  from  the  steel  beneath  or 
behind  it.  It  receives  less  strain  from  the  shaving  than 
any  other;  and  will,  in  consequence  of  these  virtues  com- 
bined, take  a  heavier  cut,  and  stand  it  longer,  than  any 
other  tool ;  but  it  is  not  so  good  for  taking  a  finishing  cut 
as  one  having  front  rake,  as  shown  in  Fig.  8. 

Having  determined  the  position  of  the  requisite  rake, 
the  next  consideration  is  that  of  the  proper  form  of  the 
cutting  edge,  the  main  principles  of  which  are  as  follows: 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  11  is  a  side  and  Fig.  12  an  end  view  of  a  tool 
having  a  combination  of  front  and  side  rake,  and  it  will 
be  understood  from  what  has  been  already  said  that  the 
front  rake  will  cause  the  pressure  of  the  shaving  or  cutting 

Fig.  11. 


Fig.  12. 


to  pull  the  tool  forward  and  into  its  cut,  while  the  side  rake 
will  act  to  pull  the  tool  along  in  the  direction  of  its  feed 
traverse.  Now,  when  the  tool  is  first  moved  to  put  on  the 
cut,  the  cross-feed  screw  in  moving  the  tool  towards  the 
lathe  centre  will  bear  on  the  sides  of  the 
threads  nearest  to  the  back  of  the  lathe, 
and  if  there  is  any  play  or  lost  motion  be- 
tween the  threads  of  the  cross-feed  screw 
and  its  nut,  then  so  soon  as  the  tool  edge 
meets  the  work  the  front  rake  will  cause  it 
(under  a  heavy  cut)  to  move  inwards  to 
whatever  amount  the  play  in  the  screw  and 
its  nut  will  permit  it  to  go.  Similarly 
the  carriage-moving  mechanism  will  not 
move  the  carriage  until  all  the  lost  motion 
in  its  parts  is  taken  up,  and  when  the  tool 
meets  the  work  the  strain  of  a  heavy  cut 
will  be  sufficient  from  the  side  rake  to  pull  the  tool  fur- 
ward  in  the  direction  of  the  feed,  and  these  two  motions 


CUTTING   TOOLS. 


35 


combined  will  cause  the  tool  to  dig  in  and  probably  break. 
To    avoid    this    difficulty  we  may  adopt  two    methods : 

Fig.  13. 


Fig.  14. 


first  we  may  take  off  the  front  rake,  leaving  the  side  rake 
intact  as  in  the  side  view,  Fig.  13,  and  the 
end  view,  Fig.  14,  which  will  prevent  the  ten- 
dency of  the  tool  to  move  in  towards  the 
lathe  centre,  and  next  we  may  set  the  tool  in 
too  far  and  be  winding  it  outwards  with 
the  cross-feed  screw  at   the  time  the  tool- 
edge  first  strikes  the  cut.      A  better  plan, 
however,  is  to  give  the  top  face  negative  top 
rake,  as  in  Fig.  15,  from  A  to  B,  in  which 
case  the  pressure  of  the  cut  or  rather  of  the 
cutting  on  the  top  face  of  the  tool  will  act 
to  a  great  extent  to  force  the  tool   back  and   away  from 
Fig.  15. 
B 


36 


COMPLETE  PRACTICAL  MACHINIST. 


the  work,  and  it  will  therefore  take  its  cut  gradually  and 
easily. 


Fig.  17. 


ROUND    NOSED    TOOLS. 

Round  nosed  tools,  such  as  shown  in  Fig.   16,  have  a 
greater  length  of  cutting  edge  to  them  (the  depth  of  the 
cuts  being  equal)  than  the  more  pointed  ones,  such  as  was 
Fig.  16.  shown  in   Fig.   3, 

and  as  a  result 
they  receive  more 
strain  from,  aud 
hence  are  more 
liable  to  run  into 
or  out  from,  the 
cut.  If  sufficient 
rake  is  given  to 
the  tool  to  obviate 
this  defect,  it  will, 
under  a  heavy  cut, 
spring  in.  It  is, 
however,  well 
adapted  to  cutting 
out  curves,  or 
taking  finishing 
cuts  on  wrought-iron  work,  which  is  so  strong  and  stiff 
as  not  to  spring  away  from  it,  because  it  can  be  used 
with  a  coarse  feed  without  leaving  deep  or  rough  tool  or 
feed  marks;  it  should,  however,  always  be  used  with  a 
slow  speed.  On  coming  into  contact  with  the  scale  or  skin 
of  the  metal,  in  case  the  work  will  not  true  up,  it  is  liable 
to  spring  away  from  its  cut  and  therefore  to  cut  deeper 
into  the  softer  than  into  the  harder  parts  of  the  metal. 
The  angles  or  sides  of  a  cutting  tool  must  not  of  necessity 
be  quite  flat  (unless  for  use  on  slight  work,  as  rods  or 
spindles),  but  slightly  curved,  and  in  all  cases  rounded  at 
the  point,  as  in  the  tool  shown  in  Fig.  17.  If  the  angles 


LATHE  AND  MACHINE  TOOLS.  37 

were  left  flat  and  the  point  sharp,  the  tool  would  leave 
deep  and  ragged  feed  marks ;  the  extreme  point,  wearing 
away  quickly,  would  soon  render  the  tool  too  dull  for  use, 
and  the  point  would  be  apt  to  break. 

For  finishing    small   wrought-iron   work    it  should    be 
ground,  as  shown  in  Fig.  18,  being  far  preferable  to  the 


Fig.  18. 


square-nosed  finishing  tools  sometimes  used  for  that  pur- 
pose, since  such  tools  do  not  turn  true  but  follow  the 
texture  of  the  metal,  cutting  deepest  in  the  softer  parts, 
especially  when  the  tool  edge  becomes  the  least  dulled  from 
use.  It  should  be  used  with  a  quick  speed  and  fine  feed. 
On  turning  work  of  one  inch  and  less  in  diameter,  it  is  an 
excellent  roughing  tool,  and  with  the  addition  of  a  little 
side  rake  is,  for  work  of  two  inches  and  less  diameter,  as 
good  a  tool  for  roughing  out  as  any  that  can  be  used. 

SQUARE-NOSED   TOOLS. 

Square-nosed  tools,  such  as  shown  in  Fig.  19,  should 

never  be  used  upon  wrought-iron,  steel,  or  brass,  for  a 

broad  cutting  surface  running  parallel  with  the  line  of 

feed  will  always,  upon  either  of  these  metals,  cause  the 

4 


38  COMPLETE  PRACTICAL  MACHINIST. 

tool  point  to  spring  into  the  softer  parts  and  to  spring 
away  from  the  harder  parts,  and,  if  the  tool  is  liable  to 
spring,  in  most  cases,  to  dig  into  the  work.  Upon  cast-iron 
work,  however,  such  a  tool  will  work  to  great  advantage 
either  for  roughing  out  or  finishing.  It  should  be  set  so 
that  its  square  nose  is  placed  quite  parallel  with  the  work  ; 

Fig.  19. 


the  feed  for  finishing  purposes  being  almost  as  broad  as 
the  nose  of  the  tool  itself,  or  say  three  revolutions  of  the 
lathe  per  inch  of  tool  travel.  It  should  be  fed  very 
evenly,  because  all  tools  possessing  a  broad  cutting  surface 
are  subservient  to  spring,  which  spring  is,  in  this  case, 
in  a  direction  to  deepen  the  cut ;  so  that,  if  more  cut  is 
taken  at  one  revolution  or  stroke  than  at  another,  the  one 
cut  will  be  deeper  than  the  other.  They  are  likewise 
liable  to  jar  or  tremble,  the  only  remedy  for  which  is  to 
grind  away  some  of  the  cutting  face  or  edgo,  making  it 
nnrrower.  For  taking  finishing  cuts  on  cast-iron,  more 
top  rake  may  be  given  to  the  tool  than  is  employed  to 
rough  it  out,  unless  the  metal  to  be  cut  is  very  hard  ; 
else  the  metal  will  be  found,  upon  inspection,  to  have 
numerous  small  holes  on  the  face  that  has  boon  cut,  ap- 
pearing as  though  it  were  very  porous.  This  occurs 


LATHE  AND  MACHINE  TOOLS.  39 

because  the  tool  has  not  cut  keenly  enough,  and  has  broken 
the  grain  of  the  metal  out  a  little  in  advance  of  the  cut, 
in  consequence  of  an  undue  pressure  sustained  by  the  metal 
at  the  moment  of  its  being  severed  by  the  tool  edge. 

The  angle  of  the  top  and  of  the  bottom  face  of  a  tool 
does  not  determine  whether  it  shall  act  as  a  scraping  or 
cutting  tool,  but  merely  affects  its  capability  of  withstanding 
the  strain  and  wear  due  to  severing  the  metal  which  it 
cuts.  Nor  is  there  any  definite  angle  at  which  the  top 
face,  B,  to  the  work  converts  the  edge  from  a  cutting  to  a 
scraping  one.  A  general  idea  may,  however,  be  obtained 
by  reference  to  Fig.  20,  the  line  A  being  in  each  case  one 
drawn  from  the  centre  of  the  work  to  the  point  of  contact 
between  the  tool  edge  and  the  work,  C  being  the  work,  and 
B  the  tool.  It  will  be  observed  that  the  angle  of  the  top 
face  of  the  tool  varies  in  each  case  with  the  line  A.  In 

Fig.  20. 


position  1,  the  tool  is  a  cutting  one;  in  2,  it  is  a  scraper; 
in  3,  it  is  a  tool  which  is  a  cutter  and  scraper  combined, 
since  it  will  actually  perform  both  functions  at  one  and  the 
same  time;  and  in  4,  it  is  a  good  cutting  tool,  the  shapes 
and  angles  of  the  tools  being  the  same  in  each  case. 


40 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  21. 


1 

A   I 


It  may  now  be  shown  that  the  amount  of  clearance 
given  by  the  bottom  rake  or  side  rake  of  a  tool  depends  upon 

the  diameter  of  the 
work  and  the  rate  of 
tool  feed.  In  Fig.  21 , 
for  example,  we  have 
three  tools  in  positions 
marked  respectively 
1,  2  and  3,  the  amount 
of  rake  being  such  as 
will  give  5  degrees  of 
clearance  from  the 
cut  in  each  case.  The 
lines  A  are  at  a  right 
angle  to  the  work 
axis,  and  we  perceive 
that  in  position  1  the 
tool  has  8?>  degrees  of 
angle  from  A,  while 
in  position  2  it  has 
10-j,  and  in  position 
3, 15  degrees  of  angle 
from  A.  This  occurs  because  the  angle  of  the  cut  to  the 
work  axis  is  greater  in  proportion  as  the  diameter  of  the 
work  is  less.  It  is  obvious,  therefore,  that  to  give  equal 
clearance,  the  bottom  rake  must  vary  for  every  different 
diameter  of  work  or  rate  of  feed. 

The  height  of  the  cutting  edge  of  a  tool  with  relation  to 
the  work  has  an  important  bearing  upon  its  cutting  quali- 
fications, since  it  affects  the  angle  of  the  top  face,  as  may 
be  seen  from  Fig.  22,  in  which  the  tool  being  placed  ex- 
tremely high,  cutting  is  bent  but  little  out  of  the  straight 
line.  It  is  obvious,  however,  that  if  the  conditions  are 
such  as  to  cause  the  tool  to  bend  under  the  pressure 
of  the  cut  and  more  at  one  part  of  a  work  revolu- 
tion than  at  another,  then  the  work  would  be  turned 
out  of  true,  or  out  of  round,  as  it  is  sometimes  termed. 


LATHE  AXD  MACHINE  TOOLS. 


41 


In  Figs.  23  and  24  are  two  tools  of  the  same  shape,  but 
placed  at  different  heights,  and  it  is  seen  from  the  dotted 

Fig.  22. 


lines  that  the  lower  the  tool  the  longer  the  line  of  resist- 
ance of  the  metal  to  the  cutting  action  of  the  tool. 

Sir  Joseph  Whitworth 

designs  his  lathes  so  that  Fig.  23. 

the  tool  requires  to  be 
forged  as  in  Fig.  25  to 
bring  its  cutting  edge 
level  with  the  axis  of  the 
work  W,  so  that  if  the 
tool  bends  under  the  cut 
pressure  (which  it  will  do  to  some  extent,  however  rigidly 
it  may  be  held),  it  will  move  in  a  direction  having  a 

minimum   of    effect    upon 
the  roundness  of  the  work. 
Thus   let  K  represent  the 
lathe  rest  and  A  the  ful- 
crum or  point  off  which  the 
tool  springs  or  bends,  and 
the    arrow   will    represent 
the  direction  of  tool  spring. 
It  follows  therefore  that 
all  tools  should  be  held  so  that  their  cutting  edges  are  as 
near  the  tool  post  as  possible,  so  as  to  avoid  their  spring- 
4 


Fig.  24. 


42 


COMPLETE  PRACTICAL  MACHINIST. 


ing,  and  to  check  as  far  as  possible  their  giving  way  to 
the  cut,  in  consequence  of  the  play  there  may  be  in  the 
slides  of  the  tool  rest ;  but  if,  from  the  nature  of  the  work 


Fig.  25. 


to  be  performed,  the  tool  must  of  necessity  stand  out  far 
from  the  tool  post,  we  should  give  the  tool  but  little  top 
rake,  and  be  sure  not  to  place  it  above  the  horizontal 
centre  of  the  work, 

The  cutting  tools  for  planing  machines  are  subservient 
to  the  same  spring,  but  the  effect  is 
Fig.  26.  ]ess  Upon  the  work,  because  if,  in  con- 

sequence of  the  spring  or  deflection,  a 
lathe  tool  approaches  the  w'ork  axis 
say  one  thousandth  of  an  inch,  then 
the  work  will  be  turned  smaller  in 
diameter  to  twice  this  amount,  whereas 
in  a  planer  tool  the  work  will  only  be 
affected  to  the  same  amount  as  the 
tool  deflects.  Fig.  26  represents  a 
ff^J  planer  tool,  the  point  A  being  the 

\      Vv^    — >r      (       fulcrum  off  which  it  springs,  and  the 
arrow    the    direction    in    which     the 
spring  occurs.    This  may  be  remedied 
so  far  as  its  effect  upon  the  work  is  concerned  by  shaping 
the  tool  so  that  its  cutting  edge  falls  vertically  under  the 
centre  of  the  tool  steel,  as  denoted  by  the  dotted  line  in 
Fig.  27,  in  which  case  the  tool  Avill  cut  very  smoothly.    ID 


LATHE  AND  MACHINE  TOOLS.  43 

other  practfce,  and   especially  for  broad    finishing   tools 
for  cast-iron,  the   cutting  edge  is  made  to  stand  about 

Fig.  27. 


Fig.  28. 


level  with  the  top  of  the  tool  steel,  the  bottom  clearance 
being  a  minimum  as  shown  by  the  line  A  in  Fipr.  2K. 


44  COMPLETE  PRACTICAL  MACHINIST. 


CUTTING    OFF    PARTING   OR   GROOVING   TOOLS. 

Tools  that  are  necessarily  slight  in  form,  especially  those 
for  use  in  a  planer,  are  more  subservient  to  the  evil  effects 
of  spring  than  those  of  stouter  body;  and  in  light  planers, 
when  the  tool  springs  in,  the  table  will  sometimes  lift  up, 
and  the  machine  become  locked,  the  cut  being  too  deep 
for  the  belt  to  drive.  The  tool  most  subservient  to  spring 
is  the  parting  or  grooving  tool  shown  in  Fig.  29,  which, 

Fig.  29. 


having  a  square  nose  and  a  broad  cutting  surface  placed 
parallel  to  the  travel  of  the  cut,  and  requiring  at  times  to 
be  slight  in  body,  combines  all  .the  elements  which  pre- 
dispose a  tool  to  spring,  to  obviate  which,  it  should  be 
placed  at  or  a  little  below  the  centre,  if  used  in  a  lathe 
uix'ier  disadvantageous  conditions,  and  bent  similarly  to 
the  tool  shown  in  Fig.  27,  if  for  use  in  a  planer,  unless 
under  favorable  conditions. 

The  point  is  made  thicker  to  give  clearance  to  the  sides, 
so  that  it  will  only  cut  at  the  end,  and  the  breadth  is  left 
wider  than  other  parts  to  compensate  in  some  measure  for 
the  lack  of  substance  in  the  thickness. 

For  use  on  wrought-iron  or  steel,  when  the  tool  is  very 
thin,  or  when  it  requires  to  enter  the  metal  to  an  unusual 
depth,  or  requires  to  stand  far  out  from  the  tool  post,  the 
tool  should  be  made  as  shown  in  Fig.  32,  which  will 
obviate  the  necessity  of  bending  the  body  of  the  tool,  and 
prevent  it  from  the  digging  in  and  breaking  off  so  com- 
mon under  those  conditions.  When  used  upon  wrought- 


LATHE  AND  MACHINE  TOOLS.  45 

iron  or  steel,  the  cutting  point  should  be  freely  supplied 
with  oil  or  soapy  water. 

This  tool  is  obviously  fed  endways  into  its  cut,  as  shown 
in  Fig.  30,  and  for   grooving    purposes   cuts  better  if  it 

Fig.  30. 


has  its  cutting  edge  set  above  the  work  axis,  but  if  the 
work  is  to  be  entirely  severed,  the  cutting  edge  mast  be  set 
level  with  the  work  axis,  and  the  feed  be  very  fine  towards 
the  last.  For  brass  work  the  top  face  should  be  ground 
depressed  towards  the  point  as  shown  in  Fig.  31,  which 

Fig.  81. 
THE  WORK 


TUB  CUTTING- 


46  COMPLETE  PRACTICAL  MACHINIST. 

will  cause  it  to  cut  more  smoothly  and  avoid  the  jarring 
or  chattering  which  is  otherwise  very  apt  to  occur. 

The  spring  tool,  shown  in  Fig.  33,  is  especially  adapted 
to  finishing  sweeps  curves*,  and  round  or  hollow  corners, 
and  may  be  used  with  equal  advantage  on  any  kind  of 

Fig.  32. 


metal  whatever,  performing  its  duty  more  perfectly  than 
any  other  form  of  tool  could,  since  the  conditions  under 
which  it  operates,  that  is,  a  very  broad  cutting  surface, 
would  cause  any  other  tool  to  dig  into  the  work.  The 
spring  tool,  however  will  spring  rather  away  from  than 


into  its  cut,  the  only  objection  to  its  use  being  that  in 
consequence  of  this  qualification  it  is  apt  to  spring  into 
the  softer  and  away  from  the  harder  parts  of  the  metal. 
Its  capability,  however,  to  take  a  broad  surface  of  cut, 


LATHE  AND  MACHINE  TOOLS.  47 

when  the  cutting  edge  stands  a  great  way  out  from  tho 
tool  post,  renders  its  use  for  some  work  imperative  as  a 
finishing  tool,  while  under  ordinary  conditions  it  will  per- 
form its  duty  sufficiently  accurately  for  all  practical  pur- 
poses. As  illustrated,  its  top  face  has  a  little  rake  to  fit  it 
for  use  on  wrought-iron ;  for  use  on  brass  and  cast-iron  the 
top  face  should  have  negative  top  rake.  In  cases  where 
the  conditions  render  it  liable  to  spring,  the  horizontal 
level  of  the  top  face  may  be  made  even  with  the  bottom 
face  of  the  body  of  the  tool,  or  the  body  of  the  tool  may 
be  bent  for  the  reasons  explained  by  Figs.  25,  26,  and  27. 
and  the  accompanying  explanations. 

The  top  face  of  a  spring  tool  should  be  filed  up  very 
smoothly  before  being  hardened,  and  it  should  never  be 
ground  upon  that  face.  The  bevel  in  the  direction  of  the 
arrow  should  be  less  for  cast-iron  and  brass  than  for  other 
metals,  but  should  in  no  case  be  excessive,  whatever  the 
inclination  of  the  top  face  may  be.  The  bend  of  the  tool 
should  be  left  soft,  the  cutting  face  being  hardened  to  a 
straw-color  for  stout  tools,  and  a  brown  for  slight  ones. 
The  face  denoted  by  the  arrow  should,  after  grinding,  be 
smoothed  with  an  oilstone.  For  use  on  steel  and  wrought- 
iron,  it  should  be  freely  supplied  with  either  soapy  or  other 
water ;  and  for  finishing  cast-iron,  such  water  may  also  be 
used;  and  that  metal  will  cut  as  clean  and  as  polished  as 
wrought-iron,  providing  the  speed  at  which  it  is  cut  is  a 
very  slow  one.  When  this  tool  is  to  be  used  a  very  long 
way  out  from  the  tool  post,  the  wooden  wedge,  shown 
driven  in  the  bend,  should  be  taken  out. 

SIDE   TOOLS    FOR   IRON. 

Side  tools  for  iron  are  subject  to  all  the  principles 
already  explained  as  governing  the  shapes  of  front  tools, 
and  differ  from  them  only  in  the  fact  that  the  cutting  end 
of  the  tool  is  bent  around  to  enable  the  cutting  edge  on  one 
side  to  cut  a  face  on  the  work  which  stands  at  right  angles 


43  COMPLETE  PRACTICAL  MACHINIST. 

with  the  straight  cut.  A  front  tool  is  used  to  take  the 
straight  cut  nearly  up  to  the  shoulder;  then  a  side  tool  is 
introduced  to  take  out  the  corner  and  cut  the  side  face. 

Fig.  34. 


A  side  tool,  whose  cutting  end  is  bent  to  the  left,  as  in 
Fig.  34,  is  called  a  left-handed  side  tool ;  and  one  which  is 
bent  to  the  right,  a  right-handed  side  tool.  The  cutting 
edges  should  form  an  acute  angle,  so  that,  when  the  point 
of  the  tool  is  cutting  out  a  corner,  either  the  point  only  or 
one  edge  is  cutting  at  a  time ;  for  if  both  of  the  edges  cut 
at  once,  the  strain  upon  the  tool  causes  it  to  spring  in. 

For  heavy  work  it  may  be  made  more  round-nosed,  and 
allowed  to  cut  all  round  the  curve,  and  with  a  coarse 
feed.  It  is  also  an  excellent  tool  for  roughing  out  sweeps 
or  curves ;  and  for  use  on  small  short  bolts,  it  may  be 
used  on  the  parallel  part  as  well  as  under  the  head. 

For  taking  out  a  corner  or  fillet  in  slight  work,  which 
is  liable  to  spring  from  the  pressure  of  the  cut — the  point 
must  be  rounded  very  little,  and  the  fillet  be  shaped  by 
operating  the  straight  and  cross  feed  of  the  lathe.  It  is 
made  right  or  left-handed  by  bending  it  in  the  required 
direction,  that  shown  being  a  left-handed  one. 

The  form  of  side  tool  shown  in  Fig.  34  is  that  most  de- 
sirable for  all  small  work  where  it  can  be  got  in  ;  and  in 
the  event  of  a  side  face  being  very  hard,  it  possesses  the 
advantage  that  the  point  of  the  tool  may  be  made  to  enter 


LATHE  AND  MACHINE  TOOLS.  49 

the  cut  first,  and,  cutting  beneath  the  hard  skin,  fracture 
it  off  without  cutting  it,  the  pressure  of  the  shaving  on  the 
tool  keeping  the  latter  to  its  cut,  as  shown  in  Fig.  35. 

Fig.  35. 


a  is  the  cutting  part  of  the  tool ;  B  is  a  shaft  with  a 
collar  on  it ;  e  is  the  side  cut  being  taken  off  the  collar, 
and  D  is  the  face,  supposed  to  be  hard.  The  cut  is  here 
shown  as  being  commenced  from  the  largest  diameter  of 
the  collar,  and  being  fed  inwards  so  that  the  point  of  the 
tool  may  cut  well  beneath  the  hard  face  D,  and  so  that 
the  pressure  of  the  cut  on  the  tool  may  keep  it  to  its  cut, 
as  already  explained  ;  but  the  tool  will  cut  equally  as  ad- 
vantageously if  the  cut  is  commenced  at  the  smallest  diam- 
eter of  the  collar  and  fed  outwards,  if  the  skin,  D,  is  not 
unusually  hard. 

Fig.  36. 


For  cutting  down  side  faces  where  there  is  but  little 

room  for  the  tool  to  pass,  the  tool  shown  in  Fig.  36  is 

used,  a  being  the  cutting  edge.     Not  much  clearance 

5 


is 


50  COMPLETE  PRACTICAL  MACHINIST. 

required  on  the  side  face  of  this  tool,  its  keenness  being 
given  by  the  angle  of  the  top  face.  Fig.  37  represents  an 

end  view  of  the  tool 

Fi9-  37-  at   work.      AY  hen 

the  work  is  of  small 
diameter,  the  cut- 
ting edge  may  be 
ground  straight  and 
set  at  a  right  angle 
to  the  work  axis, 
so  that  the  tool  may 
be  set  in  its  full 
depth  and  fed  later- 
ally. In  the  case 
of  work  of  large 
diameter,  however, 
the  tool  should  be 

formed  and  set  as  in  Fig.  38,  the  cut  being  taken  at  the 
point  E  and  fed  from  the  circumference  to  the  centre  of  the 
work.  In  some  cases  this  tool  is  forged  as  in  Fig.  38,  being 
thicker  at  the  bottom  ;  this,  however,  is  only  advantageous 
when  heavy  cuts  are  taken  and  greater  strength  is  there- 
fore necessary.  For  small  work,  such  as  facing  under  the 
heads  of  bolts,  the  cutting  end  is  bent  at  an  angle,  so  that 
the  tool  will  clear  the  work  driver  when  set  as  in  Fig.  39. 

FRONT   TOOL    FOR   BRASS   WORK. 

The  main  distinction  between  tools  for  use  on  iron  or 
steel,  and  those  for  use  on  brass  work  is,  that  the  latter  do 
not  require  any  top  rake.  Fig.  40  represents  a  front  tool 
for  brass,  and  Fig.  41  shows  the  manner  in  which  the 
cuttings  fly  off  if  the  work  is  run  as  fast  as  it  should  be. 
The  distance  the  cuttings  will  fly  after  leaving  the  tool 
gives  a  very  good  indication  of  the  efficiency  of  the  tool ; 
ordinary  composition  brass  flying  15  or  20  feet.  The 
front  tool  is  a  complete  master  tool,  filling  every  qualifi- 


LATHE  AND  MACHINE  TOOLS. 


51 


cation  for  all  plain  outside  work,  both  for  roughing  out 
and  finishing.  For  very  light  work,  or  when  the  tool 
must  be  held  far  out  from  the  tool-post,  it  may  be  given 


Fig.  38. 


TOOL 


a  little  more  rnke  on  the  bottom  or  side  faces ;  while  for 
finishing,  the  point  may  be  more  rounded  and  used  with  a 
coarser  feed,  providing  the  tool  is  rigid  and  not  liable  to 
spring.  When  held  far  out  from  the  tool-post,  the  side 


52  COMPLETE  PRACTICAL  MACHINIST. 

Fig.  39. 


Slide  Rest 


Fig.  40. 


Fig.  41. 


LATHE  AND  MACHINE  TOOLS.  53 

faces  may  be  ground  keener,  and  the  top  face  have 
negative  top  rake — that  is  to  say,  some  of  the  rake  may 
be  ground  off  the  top  face,  and  more  given  to  the  bottom 
or  side  faces ;  under  such  conditions,  also,  the  cutting  sur- 
face on  the  point  of  the  tool  may  be  reduced  as  small  as 
convenient,  so  as  to  avoid  the  liability  to  spring.  When 
ground  round-nosed  and  smoothed  with  an  oilstone,  this 
tool  gives  a  true  ami  excellent  finish  to  plain  work. 

SIDE   TOOL    FOR    BRASS   WORK. 

The  best  side  tool  for  brass  is  that  shown  in  Fig.  42. 
It  requires  little  or  no  top  rake,  and  but  little  side  or 
bottom  rake  unless  used  upon  very  slight,  work,  or  used 

Fig.  42. 


under  conditions  rendering  it  liable  to  spring.  For  tak- 
ing out  corners,  and  for  turning  out  recesses  which  do 
not  pass  entirely  through  the  metal,  it  has  no  equal. 
When  it  is  held  far  out  from  the  tool-post,  it  should 
have  the  top  face  bevelled  off,  at  an  angle  of  which  the 
cutting  part  is  the  lowest,  which  will  thus  prevent  it 
from  jarring  or  chattering,  and  from  springing  into  the 
work.  In  grinding  it,  only  the  end  should  be  ground,  so 
that  the  curve  of  the  side  of  the  tool — which  is  intended 
to  allow  the  body  of  the  tool  to  clear  the  shoulder  or 
flange  of  the  work — shall  be  preserved. 

It  will  take  a  parallel  cut,  provided  the  corner  is 
slightly  rounded,  as  easily  and  well  as  a  side  cut;  and  for 
small  work,  can  be  used  to  advantage  for  both  purposes. 


54 


COMPLETE  PRACTICAL  MACHINIST. 


It  is  a  far  better  tool  than  those  bent  around  at  the  end 
after  the  manner  of  a  boring  tool,  being  easier  to  forge, 
easier  to  grind,  and  not  so  liable  to  either  spring,  jar,  or 
chatter. 

If  a  tool  for  use  on  brass  be  made  too  keen,  it  will  give 
the  surface  of  the  brass  a  mottled  appearance,  the  color 
appearing  lighter  in  patches.  Furthermore,  the  face  of 
the  cut  will  appear  jarred  or  chattered,  and  the  cutting 
must  be  performed  at  a  slower  speed  and  feed. 

SPECIAL   FORMS    OF    LATHE   TOOLS. 

When  it  is  required  that  a  lathe  tool  shall  produce 
upon  a  number  of  pieces  of  work,  a  sweep  curve  or  fillet 
that  must  be  of  the  same  form  in  all  the  pieces,  the  diffi- 
culty arises  that  it  is  troublesome  to  grind  the  tool  with- 
out altering  its  shape.  This,  however,  may  be  avoided  by 
the  use  of  circular  cutters,  such  as  shown  in  Fig.  43,  in 


Fig.  43. 


which  the  cutter  is  cylindrical,  and  has  at  the  corner  0 
the  reverse  of  the  curve  it  is  required  to  produce  on  the 
work.  The  cutter  is  sharpened  by  grinding  the  horizontal 
face  C  which  is  set  level  with  the  face  A  of  the  holder, 
this  face  being  made  level  with  the  line  of  lathe  centres, 
when  the  holder  lies  horizontal  in  the  tool  clamp  or  tool 
post.  Clearance  is  obtained  partly  by  reason  of  the  curve 
of  the  cutter,  and  partly  by  inclining  the  face  B  against 
which  the  cutter  is  bolted. 


LATHE  AND  MACHINE  TOOLS. 


55 


Figs.  44  and  45  show  an  application  of  a  cutter  of  this 
kind  for  cutting  a  thread,  it  being  obvious  that  to  cut  a 
right-hand  thread  on  the  work, 
a  left-hand  one  must  be  provided 
on  the  cutter. 

TOOL-HOLDERS. 

To  avoid  the  trouble  of  forg- 
ing tools  and  to  give  greater 
rigidity  to  the  tool  when  it  re- 
quires to  stand  far  out  from  the 
tool-post  or  clamp,  various 
forms  of  tool-holders  are  em- 
ployed. Thus  in  Fig.  46  is  a 
tool-holder  consisting  of  a  bar  A 
having  a  hub  or  boss  H,  an  end 
view  of  the  same  being  given 
iii  Figs.  47  and  48,  in  which 
it  is  seen  that  the  tool  is  com- 
posed of  a  triangular  piece  of 
steel  held  between  two  pieces 
that  fit  inside  the  hub  of  the 
holder,  and  are  clamped  against 
the  tool  by  a  set  screw.  The 
tool  and  these  pieces  may  be 
revolved  in  the  hub  to  set  the 
tool  at  any  required  angle  as  in 
screw  cutting. 

Fig.  49  represents  a  tool-holder  H,  having  a  clamp  C 
secured  by  the  bolt  B,  and  having  a  feather  at/,  to  hold 
the  clamp  horizontal  when  bolt  B  is  loosened.  The  tool 
T  has  a  groove  on  its  side  receiving  a  feather  K,  which  is 
fast  in  the  holder,  and  therefore  holds  the  tool  at  a  con- 
stant angle.  At  S  is  a  screw  threaded  into  the  edge  of 
the  tool  T,  so  that  by  operating  this  screw  the  height  of 
the  tool  may  be  regulated.  By  this  means  the  tool  may 


CUTTER 


56  COMPLETE  PRACTICAL  MACHINIST. 

Fig.  45. 


Fig.  47. 


LATHE  AND  MACHINE  TOOLS. 


57 


Fig.  48. 


be  made  to  any  required  shape,  and  as 
it  is  sharpened  by  grinding  the  top 
face  only,  this  shape  will  be  maintained 
as  long  as  the  tool  lasts. 

Figs.  50,  51,  52  and  53  represent 
Wood  bridge's  patent  tools  and  tool- 
holder.  The  tools  consist  of  straight 
pieces  of  steel  bevelled  at  the  top  to 
give  a  certain  amount  of  side  rake, 


the  only  grinding  required  to  sharpen  them  being  on  the 


Fig.  49. 


58 


COMPLETE  PRACTICAL  MACHINIST. 


end  face.  The  tools  are  hardened  throughout,  and  hence, 
require  neither  forging  nor  tempering.  For  left-hand  tools 
the  holder  is  turned  end  for  end,  so  that  the  tool  may  be 
sustained  by  the  holder  as  near  to  the  cutting  edge  as  pos- 
sible, as  is  shown  in  Fig.  52,  which  represents  a  right  and 

Fig.  50. 


a  left-hand  tool  in  place.     The  cap  which  sets  over  the  tool 
and  receives  the  set  screw  pressure  binds  at  B,  Fig.  53,  only, 

Fio.  51. 


and  the  seat  A  in  the  holder  is  at  an  angle  so  as  to  give 
the  side  J  of  the  tool  the  necessary  clearance. 


LATHE  AND  MACHINE  TOOLS. 


59 


Fig.  54  represents  a  combined  cutting  off  tool-holder 
and  steadying  device  which  is  intended  for  cutting  from 
rods  pieces  of  an  exact  length.  The  holder  is  secured 

Fig.  52.  Fig.  53. 


in  the  tool-post,  and  has  three  screws  which  are  set  to 

steady  the  rod  (which  of  course  passes  ttirough  them). 

Fig.  54. 


On  the  side  of  the  holder  is  a  slideway  carrying  a  slide  to 
which  the  cutting-off  tool  is  fixed,  being  fed  to  its  cut  by  the 
crank  handle  shown. 

Fig.  55  represents  a  -*•  55. 

cutting-off  device  in 
which  one  leg  or  arm 
carries  steadying 
pieces  adjusted  by 
means  of  the  thumb 


60 


COMPLETE  PRACTICAL  MACHINIST. 


screw  shown,  while  the  other  arm  carries  a  gauge  and 
a  pivoted  piece  carrying  the  cutting  tool,  which  is  fed 
to  the  cut  by  the  second  arm,  which  is  pivoted  to  the  first 
one.  This  affords  a  very  ready  means  of  cutting  off 
pieces  for  small  work,  since  it  squares  the  work  ends  at 
the  same  time  that  it  cuts  it  off. 

Fig.  56  represents  a  tool-holder  for  a  shaping  machine, 

Fig.  56. 


the  tool  being  carried  in  a  tool-post  at  the  back  of  the 
holder  so  that  it  is  pulled  rather  than  pushed  to  its  cut, 
and  is  not  so  liable  to  dip  into  the  work  from  the  spring 
or  deflection.  In  place  of  a  tool-post  the  tool  or  cutter 
may  for  curves,  fillets,  etc.,  be  bolted  direct  to  the  holder, 
as  in  Fig.  57,  B  representing  the  cutter.  Fig.  58  repre- 
sents another  form  of  tool-holder  for  shaping  or  planing 
machines,  the  tool  being  carried  in  a  pivoted  tool-post  at  the 
end  of  the  holder,  so  that  it  may  be  swung  to  the  right 
or  left  as  may  be  required  ;  a  side  and  a  front  view  of  this 
tool  and  holder  in  place  upon  the  planing  machine  sliding 
head,  is  shown  in  Fig.  59.  The  tool  is  set  at  an  angle  to 
give  it  front  rake.  The  objection  to  this  form  is  that  the 
tool  is  partly  hidden  by  the  tool-post.  Applications  of 


LATHE  AND  MACHINE  TOOLS. 


61 


this  tool-holder  are  shown  in  Fig.  60,  the  direction  of  the 

feed  being  denoted  by  the  arrows.   Fig.  61  represents  an 

Fig.  57. 


o 


o 


exceedingly  useful  form  of  tool-holder  for  planing  machine 
tools,  applications  of  its  use  being  shown  as  follows. 
Figs.  62,  63,  64  and  65  show  the  application  of  such  a 

Fig.  58. 


holder  and  tools  to  the  cutting  out  of  a  T-shaped  groove 
from  solid  metal.     A  grooving  tool  first  cuts  two  grooves, 
as  shown  in  Fig.  62.  where  one  groove  is  shown  finished 
6 


62  COMPLETE  PRACTICAL  MACHINIST. 

and  the  tool  is  in  operation  on  the  second  one.     The  next 
operation  would  be  to  cut  out  the  metal  between  these  two 

Fig.  59. 


grooves,  using  the  same  tool.     In  the  absence  of  the  holder 
a  bent  tool,  such  as  in  Fig.  63,  would  be  required  to  cut 

Fig.  60. 


these  grooves,  and  the  tool  being  less  rigid  would  not  be 
able  to  carry  so  heavy  a  feed,  nor  would  it  produce  so 


LATHE  AND  MACHINE  TOOLS. 


63 


smooth  a  cut.      This  groove  being  finished,  a  tool  having 
a  single  bend  may  be  used  to  cut  out  the  enlargement  on 
one  side,  as  shown  in  Fig.  64,  carrying  down     Fig.  61. 
a  groove  at  each  end,  and  then  cutting  out 
the  metal  left    between  them.      In  the  ab- 
sence of  the  holder  the  tool  would  require 
to  have  two   bends,  as   shown    in    Fig.   65, 
and  beiag  made  of  large  steel  would  be  more 
difficult  to  forge  and  troublesome  to  use  on 
account  of  its  liability  to  spring  and  bend 
under  the  pressure  of  the  cut,  whereas,  on 
account  of  the  stiffness  of  the  holder,  its  tools 
may  be  made  of  small  pieces  of  steel. 


Fig.  62. 


Fig.  63. 


Fig.  64. 


Fig.  65. 


CHAPTER    II. 

CUTTING    SPEED    AND    FEED. 

THE  term  "  cutting  speed,"  as  applied  to  machine  tools, 
means  the  number  of  feet  of  cutting  performed  by  the  tool 
edge,  in  a  given  time,  or  what  is  the  same  thing,  the 
number  of  feet  the  shaving,  cut  by  the  tool  in  a  given 
time,  would  measure  if  extended  in  a  straight  line.  The 
term  "  feed,"  as  applied  to  a  machine  tool,  means  the  thick- 
ness of  the  cut  or  shaving  taken  by  the  tool. 

Planing  machines  being  constructed  so  that  their  tables 
run  at  a  given  and  unchangeable  speed,  their  cutting  speed 
is  fixed ;  and  the  operator  has  only,  therefore,  to  consider 
the  question  of  the  amount  of  feed  to  be  given  to  the  tool 
at  a  cut,  which  may  be  placed  at  a  maximum  by  keeping 
the  tool  as  stout  as  possible  in  proportion  to  its  work, 
making  it  as  hard  as  its  strength  will  allow,  and  fastening 
it  so  that  its  cutting  edge  will  be  as  close  to  the  tool  post 
as  circumstances  will  permit.  In  all  cases,  however,  cast- 
iron  may  be  cut  in  a  planer  with  a  coarser  feed  than  is 
possible  with  wrought-iron.  Milling  machines  should  have 
their  cutters  revolve  so  that  the  cutting  speed  of  the  largest 
diameter  of  the  cutter  does  not  exceed  18  feet  per  minute, 
at  which  speed  the  cut  taken  may  be  made,  without  injury 
to  the  cutter,  as  deep  as  the  machine  will  drive. 

It  is  only  when  we  treat  of  lathe  work  that  the  questions 
of  feed  and  speed  assume  their  real  importance,  for  there  is 
no  part  of  the  turner's  art  in  which  so  great  a  variation  of 
practice  exists  or  is  possible,  no  part  of  his  art  so  intricate 
and  deceptive,  and  none  requiring  so  much  judgment,  per- 
ception, and  watchfulness,  not  only  because  the  nature  of 
f>4 


CUTTING  SPEED  AND  FEED.  65 

the  work  to  be  performed  may  render  peculiar  conditions 
of  speed  and  feed  necessary,  but  also  because  a  tool  may 
appear  to  the  unpractised  or  even  to  the  experienced 
eye,  to  be  doing  excellent  duty,  when  it  is  really  falling  far 
short  of  the  duly  it  is  capable  of  performing.  For  all 
work  which  is  so  slight  as  to  be  very  liable  to  spring  from 
the  force  of  the  cut,  for  work  to  perform  which  a  tool  slight 
in  body  must  be  used,  and  in  cases  where  the  tool  has  to 
take  out  a  sweep  or  round  a  corner  which  has  a  break  in 
it,  a  light  or  fine  feed  must  be  employed  ;  and  it  is  there- 
fore advisable  to  let  the  cutting  speed  be  as  fast  as  the  tool 
will  stand.  But  under  all  ordinary  circumstances,  a  maxi- 
mum of  tool  feed  rather  than  of  lathe  speed  will  perform 
the  greatest  quantity  of  work  in  a  given  time.  A  keen  tool, 
used  with  a  quick  speed  and  fine  feed,  will  cut  off  a  thin  shav- 
ing with  a  rapidity  very  pleasing  to  the  eye,  but  equally  as 
deceptive  to  the  judgment;  for  under  such  a  high  rate  of 
cutting  speed,  the  tool  will  not  stand  either  a  deep  cut  or 
a  coarse  feed ;  and  the  increase  in  the  depth  of  cut  and  in 
the  feed  of  the  tool,  obtainable  by  the  employment  of  a 
slower  lathe  speed,  more  than  compensates  for  the  reduc- 
tion of  lathe  speed  necessary  to  their  attainment,  as  the 
following  remarks  will  disclose. 

Wruught-iron,  of  about  two  inches  in  diameter,  is  not 
uncommonly  turned  with  a  tool  feed  of  one  inch  of  tool 
travel  to  40  revolutions  of  the  lathe.  With  a  tool  feed  as 
fine  as  this,  it  is  possible,  on  work  of  this  size,  to  employ  a 
cutting  speed  as  high  as  27  feet  per  minute,  providing  the 
depth  of  the  cut  does  not  exceed  one-eighth  of  an  inch, 
reducing  the  diameter  of  the  work  to  If  inches.  The 
length  of  shaft  or  rod  turned  under  such  circumstances 
will  be  l^  inches  per  minute,  since  the  lathe  speed  (neces- 
sary to  give  the  tool  a  cutting  speed  of  27  feet  per  minute) 
woul.l  require  to  be  about  51  revolutions  per  minute;  and 
as  each  revolution  of  the  lathe  moves  the  tool  forward  ^ 
of  au  inch,  the  duty  performed  is  |J  of  an  inch,  or  1392 
6' 


66  COMPLETE  PRACTICAL  MACHINIST. 

inches  of  shaft  turned  per  minute,  as  before  stated.  If, 
however,  we  turn  the  same  rod  or  shaft  of  two  inch  iron, 
with  a  lathe  speed  of  36  revolutions  per  minute,  and  a  tool 
travel  of  one  inch  to  24  revolutions  of  the  lathe,  the  amount 
of  duty  performed  will  be  ||  inches,  or  li  inches  of  shaft 
turned  per  minute.  Here,  then,  we  have  a  gain  of  about 
17  per  cent,  in  favor  of  the  employment  of  the  slow  speed 
and  quick  feed.  Nor  is  this  all,  for  we  have  reduced  the 
cutting  speed  to  19  feet,  instead  of  27  feet  per  minute,  and 
the  tool  will,  in  consequence,  stand  the  cut  much  longer 
and  cut  cleaner. 

Pursuing  our  investigations  still  further,  we  find  from 
actual  test  that,  cutting  at  the  rate  of  27  feet  per  minute, 
the  tool  will  not  stand  a  cut  deeper  than  one-eighth  of  an 
inch ;  whereas  under  the  cutting  speed  of  19  feet  per 
minute,  it  will  take  a  cut  of  one-quarter  of  an  inch  in 
depth,  thus  considerably  more  than  doubling  the  duty  per- 
formed by  the  tool,  in  consequence  of  the  decreased  cutting 
speed  and  increased  feed  or  tool  travel. 

Lathe  work  of  about  three-quarters  of  an  inch  in  diameter 
may,  if  there  is  no  break  in  the  cut,  be  turned  at  a  cutting 
speed  of  as  much  as  36  feet  per  minute,  the  feed  being  one 
inch  of  tool  travel  to  about  25  revolutions  of  the  lathe.  The 
revolutions  per  minute  of  the  lathe,  necessary  to  give  such 
a  rate  of  cutting  speed,  will  be  about  183;  the  duty  per- 
formed will  therefore  be  V^or  7T5g  inches  of  three-quarter 
inch  iron  turned  per  minute.  A  feed  of  one  inch  of  tool 
travel  to  25  revolutions  of  the  lathe  is  greater  than  is  gen- 
erally employed  upon  work  of  so  small  a  diameter  as  three- 
quarter  inch,  but  is  not  too  great  for  the  generality  of  work 
of  such  a  size ;  for  the  tool  will  stand  either  a  roughing  or 
smoothing  cut  at  that  speed,  unless  in  the  exceptional  case 
of  the  work  being  so  long  as  to  cause  it  to  spring  away  from 
the  tool.  Under  these  circumstances  the  feed  may  be  re- 
duced to  one  inch  of  tool  travel  to  30  or  40  revolutions 
of  the  lathe,  according  to  the  length  and  depth  of  the  cut. 


CUTTING  SPEED  AND  FEED. 


67 


It  will  be  observed  that  the  cutting  speed  given,  for  work 
of  three-quarter  inch  diameter,  is  nearly  double  that  given 
as  the  most  advantageous  for  work  of  two  inches  diameter, 
while  the  feed  or  tool  travel  is  nearly  the  same  in  both 
cases ;  the  reason  of  this  is  that  the  tool  can  be  ground 
much  keener  for  the  smaller  sized  than  it  could  be  for  the 
larger  sized  work,  and,  furthermore,  because  the  metal, 
being  cut  off  the  smaller  work,  is  not  so  well  supported  by 
the  metal  behind  it  as  is  the  metal  being  cut  off  the  larger 
work,  and,  in  consequence,  places  less  strain  upon  the  tool 
point,  as  illustrated  in  Figs.  66  and  67. 


Fig.  67. 


B  is  a  shaft,  and  C  is  the  tool  in  both  cases.  The  dotted 
line  a,  in  Fig.  66,  does  not,  it  will  be  observed,  pass  through 
so  much  of  the  metal  of  the  shaft  B,  as  does  the  dotted  line 
a,  of  the  shaft  B,  in  Fig.  67.  The  metal  in  contact  with  the 


68  COMPLETE  PRACTICAL  MACHINIST. 

point  of  the  tool  in  Fig.  66,  is  not,  therefore,  so  well  sup- 
ported by  the  metal  behind  it  as  is  the  metal  in  contact  with 
the  point  of  the  tool  in  Fig.  67,  the  result  being  that  the 
tool,  taking  a  cut  on  the  smaller  shaft  equal  in  depth  to 
that  taken  by  the  tool  on  the  larger  one,  may  have  a  higher 
rate  of  cutting  speed  without  sustaining  any  more  force 
from  the  cut,  the  difference  in  the  resistance  of  the  metal 
to  the  tools  being  equalized  by  the  increased  speed  of  the 
smaller  shaft. 

These  conditions  are  reversed  in  the  case  of  boring,  the 
metal,  being  cut  in  a  small  hole,  being  better  supported  by 
the  metal  behind  it  than  is  the  case  in  a  larger  hole  or 
bore.  This  may  be  overcome  by  making  the  boring  tool 
point  cut  b^low  the  horizontal  centre  of  the  work,  while 
the  body  of  the  tool  may,  to  keep  it  stout  enough,  be  kept 
in  the  centre  of  the  hole.  But  in  a  large  bore,  the  effect  is 
not  so  seriously  encountered,  because  of  the  nearer  approach 
of  the  circle  to  the  straight  line. 

On  heavy  work  it  is  specially  desirable  to  have  the  tool 
stand  a  long  time  without  being  taken  out  to  grind,  for  the 
following  reasons :  1.  It  takes  longer  to  stop  and  start  the 
lathe,  and  to  take  out  and  replace  the  tool.  2.  It  takes 
longer  to  readjust  the  tool  to  its  cut.  3.  It  takes  more  time 
to  put  the  feed  motion  into  gear  again.  4.  The  feed  motion 
is  very  slow  to  travel  the  tool  up  and  into  its  cut,  and  to 
take  up  its  play  or  lost  motion.  5.  Lastly,  the  tool  should 
take  a  great  many  more  feet  of  cut,  at  one  grinding,  than 
is  the  case  with  a  tool  for  small  work. 

A  tool  used  on  work  5  inches  diameter  (the  lathe  making 
20  revolutions  to  feed  the  tool  one  inch)  would  perform 
314  feet  of  cutting  in  travelling  a  foot,  the  lathe  having,  of 
course,  performed  240  revolutions ;  while  one  used  on  work 
10  feet  in  diameter  (with  the  same  ratio  of  speed)  will  have 
performed  314  feet  of  cutting  when  the  tool  has  travelled 
half  an  inch,  and  the  lathe  made  10  revolutions  only.  In 
practice,  howev?r,  the  feed  for  larger  work  is  increased 


CUTTING  SPEED  AND  FEED. 


in  a  far  greater  ratio  than  the  cutting  speed  is  diminished, 
as  compared  with  small  work;  but  in  all  cases  the  old 
axiom  and  poetical  couplet  holds  good,  that 

"A  quick  feed 
And  slow  speed  " 

are  the  most  expeditious  for  cutting  off  a  quantity  of  metal, 
and  in  the  case  of  cast-iron,  for  finishing  it  also. 

A  positive  or  constant  rate  of  cutting  speed  for  large 
work  cannot  be  given,  because  the  hardness  of  the  metal, 
the  liability  of  the  work  to  spring  in  consequence  of  its 
shape,  the  distance  of  the  point  of  the  tool  from  the  tool 
post,  aud  other  causes  already  explained,  may  render  a 
deviation  necessary,  but  the  following  are  the  approximate 
speeds  and  feeds  for  ordinary  work  : 

TABLES   OF   CUTTING   SPEEDS   AND   FEEDS. 

Table  for  Steel. 


ROUGHING    CUTS. 

FINISHING  CUTS. 

Diameter  of  work 
in  inches. 

Speed  in  feet 
per  minute. 

Feed. 

Speed  in  feet 
per  minute. 

Feed. 

1  and  less 

20 

25 

20 

30 

1     to     2 

18 

25 

18 

30 

2     to     3 

18 

25 

15 

80 

3     to     6 

15 

20 

15 

30 

For  Wrought-Iron. 


ROUGHING    CUTS. 


FINISHING  CUTS. 


Diameter  of  work 

Speed  in  feet 

Speed  in  feet 

in  inches. 

per  minute. 

Feed. 

per  minute. 

1  and  less 

35 

25 

38 

1     to     2 

25 

20 

30 

2     to     4 

25 

20 

25 

4     to     6 

23 

20 

23 

6     to  12 

20 

15 

23 

12    to  20 

18 

12 

18 

Feed. 
30 

30 
25 
25 
?() 
16 


70  COMPLETE  PRACTICAL  MACHINIST. 

For  Cast-Iron. 


ROUGHING   CUTS. 

FINISHING  CUTS. 

Diameter  of  work 
in  inches. 

Speed  in  feet 
per  minute. 

Feed. 

Speed  in  feet 
per  minute. 

Feed. 

1  and  less 

38 

20 

38 

?0 

1     to     2 

35 

20 

35 

16 

2     to     4 

30 

20 

30 

10 

4     to     6 

25 

16 

25 

6 

6     to  12 

20 

14 

20 

6 

12     to  20 

20 

10 

20 

4 

For  Brass. 


ROUGHING   CUTS. 

FINISHING   CUTS. 

Diameter  of  work 
in  inches. 

Speed  in  feet 
per  minute. 

Feed. 

Speed  in  feet 
per  minute. 

Feed. 
25 

25 

1  and  less 
1     to     2 

120 

100 

25 
25 

120 
100 

2     to    4 

80 

25 

100 

25 

4    to     6 

70 

25 

70 

25 

6     to  12 

60 

25 

70 

25 

For  Copper. 


ROUGHING   CUTS. 

FINISHING  CUTS. 

Diameter  of  work 

Speed  in  feet 

Speed  in  feet 

in  inches. 

per  minute. 

Feed. 

pei-  minute. 

Feed. 

1  and  less 

350 

25 

400 

25 

2    to     5 

250 

25 

300 

25 

5     to  12 

200 

25 

200 

25 

12    to  20 

150 

25 

150 

30 

In  cases  where  the  cuts  are  unusually  long  ones,  the 
cutting  speeds  may  be  slightly  reduced  except  in  the  case 
of  copper.  All  the  tools  we  have  so  far  described  may 
justly  be  termed  master  tools,  for  work  on  external  sur- 
faces, each  entirely  filling  its  arena,  and  all  other  tools  used 
on  outside  work  are  simply  modifications  called  into  requi- 
sition to  suit  exceptional  cases. 


CHAPTER   III. 

BORING   TOOLS    FOR   LATHE  WORK. 

STANDARD  bits  and  reamers  have  superseded  the  use  of 
boring  tools  for  all  special  and  many  other  purposes,  but 
there  are  numerous  cases  where  a  boring  tool  cannot  be  dis- 
pensed with,  especially  in  repairing  shops  and  for  promis- 
cuous work. 

Boring  tools  for  use  on  lathe  work  require  to  be  shaped 
with  greater  exactitude  than  any  other  lathe  tools,  for  the 
reason  that  they  are  slighter  in  body  in  proportion  to  the 
duty  required  of  them  than  any  other;  and  as  a  rule,  the 
cutting  edges  standing  further  out  from  the  tool  post  or 
clamp,  the  body  of  the  tool  is  more  subject  to  spring  from 
the  strain  of  the  cut.  It  is  obvious  that,  if  the  hole  to  be 
bored  out  is  a  long  one,  the  cutting  edge  of  the  tool  will 
become  dull  at  the  end  of  the  hole  as  compared  to  what  it 
was  at  the  commencement  (a  remark  which,  of  course, 
applies  to  all  tools) ;  but  in  tools  stout  in  proportion  to  the 
duty  required  of  them,  and  held  close  in  to  the  tool  post, 
the  effect  of  the  slight  wear  of  the  cutting  edge,  due  to  a 
finishing  cut,  is  not  practically  appreciable.  In  the  case 
of  a  boring  tool,  however,  the  distance  of  the  cutting  edge 
from  the  tool  post  renders  the  slightest  variation  in  the 
cutting  capability  of  the  tool  sufficient  to  affect  the  work, 
as  may  be  experienced  by  boring  out  a  hole  half  of  its 
length,  and  then  merely  exerting  a  pressure  on  the  body 
of  the  tool,  as  near  the  entrance  of  the  hole  as  possible, 
with  the  fingers,  when  the  size  of  the  last  half  of  the  hole 
will  be  found  to  have  varied  according  to  the  direction  in 

71 


72 


COMPLETE  PRACTICAL  MACHINIST. 


which  the  pressure  was  placed.  As  a  result  of  this  extreme 
sensitiveness  to  spring,  the  tool  is  apt  to  spring  away  from 
the  cut  as  the  boring  proceeds,  thus  leaving  the  hole  smaller 
at  the  back  than  at  the  front  end.  To  remedy  this  defect, 
several  very  fine  finishing  cuts  may  be  taken ;  but  a  better 
plan  is  to  so  shape  the  tool  that  its  spring  will  be  in  a  direc- 
tion the  least  liable  to  affect  the  size  of  the  bore  of  the 
work. 

The  pressure  on  the  cutting  edge  of  a  tool  acts  in  two 
directions,  the  one  vertical,  the  other  lateral.  The  down- 
ward pressure  remains,  under  equal  conditions,  at  all  times 
the  same ;  the  lateral  pressure  varies  according  to  the  direc- 

Fig.  68. 


tiou  of  the  plane  of  the  cutting  edge  of  the  tool  to  the  line 
or  direction  in  which  the  tool  travels :  the  general  direction 
of  the  pressure  being  at  a  right  angle  to  the  general  direction 
of  the  plane  of  the  cutting  edge.  For  example,  the  lateral 
pressure,  and  hence  the  spring  of  the  various  tools,  shown 
in  Fig.  68,  will  be  in  each  case  in  the  direction  denoted  by 
the  dotted  lines.  D  is  a  section  of  a  piece  of  metal  requir- 
ing the  three  inside  collars  to  be  cut  out;  A,  B,  and  C  are 
variously  shaped  boring  tools,  from  which  it  will  be  seen 
that  A  would  leave  the  cut  in  proportion  as  it  suffered  from 
spring,  which  would  increase  as  the  tool  edge  became  dull, 
and  that  the  cut  forms  a  wedge,  tending  to  force  the  tool 
towards  the  centre  of  the  work.  B  would  neither  spring 


BORING   TOOLS.  FOR  LATHE   WORK.  73 

into  nor  away  from  the  cut,  but  would  simply  require  more 
power  to  feed  it  as  the  edge  became  dulled ;  while  C  would 
have  a  tendency  to  run  into  the  cut  in  proportion  as  it 
springs ;  and  as  the  tool  edge  became  dull,  it  would  force 
the  tool  point  deeper  and  deeper  into  the  cut  until  some- 
thing gave  way.  Now,  in  addition  to  this  consideration 
of  spring,  we  have  the  relative  keenness  of  the  tools,  it 
being  obvious  at  a  glance  that  (independent  of  any  top  rake 
or  lip)  C  is  the  keenest,  and  A  the  least  keen  tool ;  and 
since  wrought-iron  requires  the  keenest,  cast-iron  a  medium, 
and  brass  the  least  keen  tool,  it  follows  that  we  may  accept, 
as  a  rule,  C  for  wrought-iron,  B  for  cast-iron,  and  A  for 
brass  work.  To  this  rule  there  are,  however,  variations  to 
be  made  to  suit  exceptional  cases,  such  for  instance  as  when. 
a  hole  terminates  in  solid  metal  and  has  a  flat  bottom,  in 
which  case  the  tool  B  (slightly  modified  towards  the  form 
of  tool  C)  must  be  employed.  Or  suppose  a  hole  in  cast- 
iron  to  be,  as  is  often  the  case,  very  hard  at  and  near  the 
surface  of  the  metal.  Tool  A  would  commence  cutting  the 
hard  surface,  and,  becoming  dull,  would  spring  away  from 
the  cut  in  spite  of  all  that  could  be  done  to  prevent  it ; 
while  tool  B  would  commence  to  cut  both  the  hard  and  the 
soft  metal  together,  the  cutting  edge  wearing  rapidly  away 
where  it  came  into  contact  with  the  hard  surface  of  the  metal ; 
and  these  conditions  would,  in  both  cases,  continue  during 
the  whole  operation  of  boring,  rendering  it  difficult  and 
tardy.  But  if  the  tool  C  were  employed,  the  point  of  the 
tool  would  commence  cutting  the  soft  part  of  the  metal 
first,  and  would  undermine  the  hard  surface,  and  (from  the 
pressure)  break  it  instead  of  cutting  it  away,  as  shown  in 
Fig.  69,  in  which  a  is  the  point  of  the  tool,  and  from  a  to  B 
is  the  cutting  edge  ;  the  dotted  lines,  c  and  D,  represent  the 
depth  of  the  cut,  c  being  the  inside  skin  of  the  metal,  sup- 
posed to  be  hard. 

The  angle  at  which  the  cutting  edge  stands  to  the  cut 
causes  the  pressure,  due  to  the  bending  and  fracturing  of 
7 


74  COMPLETE  PRACTICAL  MACHINIST. 

the  shaving,  to  be  in  the  direction  of  e,  which  keeps  the 
tool  point  into  its  cut ;  while  the  resistance  of  the  tool 
point  to  this  force,  reacting  upon  the  cut,  from  a  to  B, 
causes  the  hard  skin  to  break  away. 

Fig.  69. 


When  a  cut  is  being  taken  which  is  not  sufficient  to  clean 
up  or  true  the  work,  less  top  rake  must  be  given,  as  a  very 
keen  tool  loses  its  edge  more  quickly  than  one  less  keen. 
The  reason  for  taking  the  rake  off  the  top  of  a  tool  is  that, 
if  it  were  taken  off  the  bottom,  the  cutting  edge  would  not 
be  so  well  supported  by  the  metal,  and  would  have  a  ten- 
dency to  scrape,  which  rule  applies  both  to  inside  and  out- 
side cuts.  For  brass  work,  top  rake  is  never  applied,  because 
it  would  cause  the  tool  to  jar  and  cut  roughly,  bottom  rake 
alone  being  sufficient  to  give  a  tool  for  brass  the  requisite 
keenness. 

The  application  of  top  rake  or  lip  to  a  boring  tool  lessens 
the  strain  due  to  serving  the  metal ;  by  presenting  a  keener 
cutting  edge,  it  lessens  the  tendency  to  lateral  spring,  and 
increases  that  to  vertical  spring,  and  is  beneficial  in  all 
cases  in  which  it  can  be  employed.  Upon  wrought-iron 
and  steel  it  is  indispensable  ;  upon  cast  it  may  be  employed 
to  a  limited  degree ;  and  upon  brass  it  is  inadmissible  by 
reason  of  its  causing  the  tool  to  either  jar  or  chatter.  In 
Fig.  70,  B  represents  a  section  of  the  work,  No.  1  represents 
a  boring  tool  with  top  rake,  for  wrought-iron,  and  No.  2  a 
tool  without  top  rake,  for  brass  work,  which  may  be  also 
used  for  cast-iron  when  the  tool  stands  a  long  way  out  from 
the  tool  post  or  clamp,  under  which  circumstances  it  is 


SORING  TOOLS  FOR  LATHE   WORK. 


75 


Fig.  70. 


liable  to  jar  or  chatter.  A  tool  for  use  on  wrought-iron 
should  have  the  same  amount  of  top  rake,  no  matter  how 
far  it  stands  out  from  the  tool  post ;  whereas  one  for  use  on 
cast-iron  or  brass  requires  to  be  the  less  keen  the  further  it 
stands  out  from  the  tool  post.  To  take  a  very  smooth  cut 
on  brass  work,  the  top  face  of 
the  tool,  shown  at  2  in  Fig.  70, 
must  be  ground  off,  as  denoted  by 
the  dotted  line. 

We  have  now  to  consider  the 
most  desirable  shape  for  the  cor- 
ner of  the  cutting  edge.  A  posi- 
tively sharp  corner,  unless  for  a 
special  purpose,  is  very  undesira- 
ble, because  the  extreme  point 
soon  wears  away,  leaving  the  cut- 
ting qualification  of  the  tool 
almost  destroyed,  and  because  it 
leaves  the  work  rough,  and  can 
only  be  employed  with  a  very 
fine  feed.  It  may  be  accepted  as 
a  general  rule  that,  for  roughing 
cuts,  on  brass  work,  the  corner 
should  be  sufficiently  rounded  to 
give  strength  to  the  tool  point; 
while,  in  finishing  cuts,  the  point 
may  be  made  as  round  as  possible 
without  causing  the  tool  to  jar  or 
chatter.  Now,  since  the  tendency 
of  the  tool  to  jar  or  chatter  upon 
all  metals  depends  upon  four 
points,  namely,  the  distance  it  stands  out  from  the  tool 
post,  the  amount  of  top  rake,  the  acuteness  or  keenness  of 
the  general  outline  of  the  tool,  and  the  shape  of  the  cutting 
corner,  it  will  readily  be  perceived  that  considerable  judg- 
ment is  required  to  determine  the  most  desirable  form  for 


76 


COMPLETE  PRACTICAL  MACHINIST. 


any  particular  conditions,  and  that  it  is  only  by  understand- 
ing the  principles  governing  the  conditions  that  a  tool  to 
suit  them  may  be  at  once  formed. 

In  Fig.  71  will  be  found  the  various  forms  of  boring 
tools  for  ordinary  use.  No.  1  is  for  use  when  the  conditions 
admit  of  a  heavy  cut  on  wrought-iron.  No.  2  is  for  use  on 
wrought-iron  when  the  tool  stands  so  far  from  the  tool  post 
as  to  be  necessarily  subject  to  spring.  No.  3  is  to  cut  out 
a  square  corner  at  the  bottom  of  a  hole  in  wrought-iron. 
No.  4  is  for  taking  out  a  heavy  cut  in  cast-iron.  No.  5  is 


Fig.  71. 


for  taking  out  a  finishing  cut  in  cast-iron  when  the  tool  is 
proportionally  stout,  and  hence  not  liable  to  spring  or 
chatter :  the  point  being  flat,  the  cutting  being  performed 
by  the  front  corner,  and  the  back  part  being  adjusted  to 
merely  scrape.  No.  6  is  for  use  on  cast-iron  under  con- 
ditions in  which  the  tool  is  liable  to  jar  or  spring. 

An  inspection  of  all  these  tools  will  disclose  that  the  tool 
point  is  more  rounded  for  favorable  conditions,  that  is,  when 
the  body  of  the  tool  is  stout,  and  the  cutting  edge  is  not 
held  far  out  from  the  tool  post;  that,  to  prevent  jarring,  the 


SORING   TOOLS  FOR  LATHE   WORK.  77 

point  of  the  tool  is  made  less  round,  which  is  done  to  reduce 
the  cutting  surface  of  the  tool  edge  (since  it  is  apparent 
that,  with  a  given  depth  of  cut,  the  round-pointed  tool  will 
present  the  most  cutting  edge  to  the  cut)  ;  and  that,  to 
further  prevent  jarring  or  chattering,  the  leading  part  of 
the  cutting  edge  is  ground  at  an  angle ;  while,  as  another 
precaution  against  that  evil,  the  general  form  of  the  tool  is 
varied  from  that  of  tool  C,  in  Fig.  68,  towards  that  of  tool 
A  in  the  same  figure;  while  for  brass  work,  no  top  rake 
or  lip  is  employed,  but  the  tool  is  bevelled  off  to  suit  those 
cases  in  which  it  is  liable  to  excessive  spring.  It  is  obvious 
that  the  feed  may  be  coarser  for  a  round-nosed  than  for  a 
more  acute  tool,  and  that,  the  rounder  the  nose,  the  smoother 
the  cut  will  be  with  the  same  rate  of  feed. 

For  heavy  duty  on  wrought-iron,  whether  in  large  or 
small  holes,  the  boring  tool,  represented  in  Fig.  72,  has  no 

Fig.  72. 


equal.  The  rake  on  the  top  face  makes  the  cutting  edge  per- 
form its  duty  on  the  front  edge,  and  the  strain  due  to  bending 
the  shaving  tends  to  draw  the  tool  to  its  cut,  giving  it  an 
inclination  to  feed  itself  forward,  thus  relieving  the  feed 
screw  of  a  part  'f  the  duty  due  to  the  strain  of  feeding. 

The  cutting  edge  should  not  stand  above  the  horizontal 
level  of  the  top  of  the  tool  body  ;  otherwise,  so  stout  a  tool 
could  not  be  gotten  into  a  given  size  of  hole ;  a  consideration 
which,  in  small  holes,  is  of  the  utmost  importance.  For 


78 


COMPLETE  PRACTICAL  MACHINIST. 


similar  duty  on  brass,  the  tool  shown  in  Fig.  73  is  the  best 
that  can  be  employed. 

Fig.  73. 

BORING  TOOL    FOR  BRASS. 


Fig.74. 


When,  upon  brass  work,  a  loring  tool  has  a  broad  cutting 
surface,  such  as  is  required  to  cut  a  recess,  the  only  way  to 
prevent  extreme  chattering  and  jarring  is  to  grind  oft'  the 
top  face,  giving  it  negative  top  rake,  as  shown  in  Fig.  74  : 
a  being  a  section  of  the  body  of  the  tool,  B  the  cutting 
part,  and  c  the  outline  of  the  hole.  B,  being  the  lowest  point 
of  the  top  face,  possesses  negative  top  rake,  and  a  corre- 
sponding tendency  to  scrape  rather  than  cut  keenly.  The 
point  B  should  always  be  above 
the  centre  of  the  hole,  so  that,  in 
springing,  it  will  spring  away  from 
and  not  into  its  cut.  A  boring  tool, 
slight  in  proportion  to  its  duty,  and 
for  use  upon  small  wrought-iron 
work,  should  always  be  placed  so 
that  its  cutting  edge  is  a  little 
below  the  centre  of  the  hole,  in 
which  case  the  bottom  of  the  body 
of  the  tool  is  liable,  in  small  holes, 

to  bear  against  the  bottom  of  the  hole,  unless  the  cutting 
part  is  made  to  be  a  little  below  the  centre  of  the  body  of 
the  tool,  rendering  it  rather  difficult  to  grind  on  the  top 
face.  It  is  not,  however,  imperatively  necessary  to  grind  it 
there,  since  it  can  be  sharpened  by  grinding  the  side  faces; 


BORING   TOOLS  FOR  LATHE   WORK.  7ft 

and  the  advantage  gained  by  being  enabled  to  get,  into  a 
given  sized  hole,  a  stouter  tool  than  otherwise  could  be 
done,  and,  as  a  result,  to  take  deeper  and  more  nearly 
parallel  cuts  (for  such  tools  generally  spring  off  their  cut 
at  the  back  end  of  the  hole,  leaving  it  taper  unless  several 
light  cuts  are  taken  out),  more  than  compensates  for  the 
extra  wear  of  the  tool,  consequent  upon  being  able  to  grind 
it  upon  one  part  only. 

Boring  tools  for  use  on  w  rough  t-iron,  cast-iron,  steel  or 
copper,  require  very  little  side  or  bottom  rake,  only  suffi- 
cient, in  fact,  to  well  clear  the  sides  of  the  cut,  and  the 
straighter  these  side  faces  are  kept  the  stronger  the  tool ; 
and  the  better  the  cutting  edges  are  supported  by  the 
metal  behind  them,  the  longer  will  they  stand  without 
regrinding. 

When  boring  light  brass  work,  it  is  well  to  hold  a  brush 
near  the  entrance  of  the  hole,  to  prevent  the  turnings  from 
flying  about  the  shop ;  while  cutting  tools  for  outside  brass 
work  may  have  a  split-leather  washer  forced  over  the  body 
near  the  cutting  end  for  the  same  purpose. 

After  a  piece  of  brass  or  cast-iron  work  has  been  bored 
and  taken  out  of  the  lathe,  and  is  found  on  trial  to  fit  a 
little  too  tight,  it  may,  if  it  is  difficult  to  chuck  it  true 
again,  be  eased  by  a  half-round  scraper,  as  follows  :  Take 
an  old  half-round,  smooth  file,  and  grind  the  teeth  com- 
pletely out  of  the  flat  face ;  then  grind  the  edges  to  an 
angle  sufficiently  acute  to  cut  freely,  as  a  scraper ;  then 
rechuck  the  work  in  the  lathe  as  nearly  true  as  possible, 
and  revolve  it  at  such  a  speed  that  the  scraper  will  cut  at 
about  380  feet  per  minute ;  then  apply  the  scraper  edge  to 
the  bore  of  the  hole  at  the  bottom,  moving  it  along  the  bore 
and  holding  it  firmly.  If  the  flat  face  and  the  bevelled 
edge  of  the  scraper  be  ground  true  and  even,  and  care  is 
taken  in  using  it  to  take  out  the  metal  only  where  required, 
this  tool  will  perform  excellent  duty  and  cut  very  smoothly. 
It  may  also  be  used  to  advantage  to  ease  out  by  hand  the 


80 


COMPLETE  PRACTICAL  MACHINIST. 


narrow  places  of  a  hole  that  is  oval,  or  the  small  end  of  one 
that  is  taper  and  requires  to  be  made  parallel.  The 
smoothness  of  its  work  is  much  improved  by  smoothing  its 


edge  upon  an  oilstone.  Here  it  may  be  well  to  state  that 
the  application  of  an  oilstone  to  the  cutting  edges  of  a 
boring  tool  increases  its  tendency  to  chatter ;  if,  therefore, 
a  hole  requires  to  be  made  unusually  smooth,  the  tool 


BORING   TOOLS  FOR  LATHE   WORK.  81 

must  be  given  less  top  rake  and  may  then  be  oilstoned. 
In  many  cases  a  tool  may  be  prevented  from  chattering 
by  holding  it  with  the  fingers  as  near  the  entrance  of  the 
hole  as  possible. 

Fig.  75  represents  a  boring  tool,  composed  of  a  piece  of 
octagon  steel  lying  in  a  holder  or  seat  E,  which  may  be 
so  set  in  the  tool-post  as  to  support  the  tool  as  near  to 
the  cutting  edge  as  the  depth  of  the  hole  to  be  bored  will 
permit. 

Fig.  76  represents  a  boring  tool  made  of  round  steel, 
and  clamped  between  two  pieces  1  and  2,  so  that  the  tool 

Fig.  76. 


may  be  readily  adjusted  to  the  work  by  revolving  it  ou 
its  axis,  and  placed  to  project  through  the  clamps  as  far 
as  necessary  for  the  work,  and  to  facilitate  this  the  tool  is 
sometimes  separate  and  secured  by  a  set  screw. 


82  COMPLETE  PRACTICAL   MACHINIST. 

BORING   TOOL  HOLDERS. 

For  use  on  holes  too  small  to  admit  of  a  bar  having  a 
sliding  head,  which  are  usually  bored  with  a  slide  rest  tool, 
a  boring  tool  holder  may  be  employed  to  great  advantage. 
Such  a  holder  may  be  made  by  squaring  or  flattening  one 
end  of  a  round  bar  of  iron  so  that  it  will  fit  into  the  tool 
post  of  the  lathe,  and  cutting  into  the  opposite  end  a  groove 
to  receive  a  short  boring  tool,  the  latter  being  fastened  to 
its  place  by  set  screws  provided  in  the  holder  or  by  being 
wedged  in  with  a  small  wedge.  Various  sizes  of  such 
holders  should  be  made,  the  larger  sizes  being  provided 
with  set  screws  to  hold  the  tool.  For  use  in  holes  of  from 
two  to  eight  inches  bore,  such  an  appliance  is  invaluable, 
especially  if  the  hole  to  be  bored  is  of  unusual  depth  ; 
because  the  bar  may  be  made  very  stout  in  proportion  to 
the  size  of  the  hole,  and  will,  therefore,  stand  a  depth  of 
cut  and  a  rate  of  feed  totally  impracticable  with  an  ordi- 
nary boring  tool,  and  will  not  spring  away  from  its  cut 
towards  the  back  end  of  the  hole,  as  boring  tools  are  apt  to 
do.  Furthermore,  the  cutting  tools,  being  small,  are  easily 
forged,  ground  up,  and  renewed  when  worn  out ;  and  the 
bar  maintains  its  original  length,  which  may  be  made  to 
suit  the  depth  of  hole  required  to  be  bored  ;  while  a  boring 
tool  becomes  shorter  each  time  it  requires  reforging. 

For  truing  out  broad  recesses  in  large  work,  the  slot  in 
the  end  may  be  made  large  enough  to  receive  two  tools, 
one  to  turn  the  inside  and  the  other  the  outside  of  the 
recess. 

For  use  upon  holes  of  a  very  large  bore,  or  upon  outside 
work  in  which  the  tool  requires  to  stand  a  long  way  out 
from  the  slide  rest,  as  sometimes  occurs  when  the  diameter 
of  the  work  is  so  near  the  full  size,  the  lathe  will  swing ; 
that  there  is  not  sufficient  room  for  the  slide  rest  of  the 
lathe  to  pass  under  the  work,  a  square  tool  holder  should 


SORING  TOOLS  FOR  LATHE   WORK.  83 

be  employed,  such  tool  holder  being  a  stout  bar  of  square 
iron,  say  2?  inches  square,  and  having  a  complete  tool  box 
on  one  end,  the  tool  box  being  provided  with  two  stout 
steel  set  screws. 


CHAPTEK    IV. 

SCREW-CUTTING   TOOLS. 

LATHE  tools  for  cutting  screws  have  necessarily,  from 
the  nature  of  their  duty,  a  comparatively  broad  cutting 
surface,  rendering  them  very  subject  to  spring.  Those 
used  for  V  threads,  being  ground  to  fit  the  V  of  the  thread, 
are,  in  consequence,  weak  and  liable  to  break ;  to  avoid 
which  they  should  only  be  given  enough  bottom  rake  to 
clear  the  thread  well,  and  top  rake  sufficient  to  made  them 
cut  clean.  They  are  used  at  a  slow  rate  of  cutting  speed, 
and  may  therefore  be  lowered  to  a  straw-colored  temper 
(as  reducing  the  temper  strengthens  a  tool).  Firmness 
and  strength  are  of  great  importance  to  this  class  of  tool, 
so  that  it  should  be  fastened  with  the  cutting  edge  as  near 
to  the  tool  post  as  is  convenient. 

For  use  on  wrought-iron,  the  V  or  thread-cutting  tool  is 
sometimes  given  side  rake ;  but  this  is  not  a  necessity  and 
is  of  doubtful  utility,  because  the  advantage  gained  by  its 
tendency  to  assist  in  feeding  itself  is  quite  counterbalanced 
by  its  increased  liability  to  break  at  the  point.  It  should 
always  be  placed  to  cut  at  the  centre  of  the  work. 

If  the  pitch  of  the  screw  to  be  cut  is  very  coarse,  a  tool 
nearly  one-half  of  the  width  of  the  space  between  one 
thread  and  the  next  should  be  employed,  so  as  to  avoid 
the  spring  which  a  tool  of  the  full  width  would  undergo. 
After  taking  several  cuts,  the  tool  must  be  moved  laterally 
to  the  amount  of  its  width,  and  cuts  taken  off  as  before 
until  the  tool  has  cut  somewhat  deeper  than  it  did  before 
84 


SCREW-CUTTING   TOOLS. 


85 


being  moved,  when  it  must  be  placed  back  again  in  its 
first  position,  and  the  process  repeated  until  the  required 
depth  of  thread  is  attained. 

Fig.  77. 


Fig.  77  represents  a  thread  or  screw  during  the  above 
described  process  of  cutting,  a  a  a  is  the  groove  or  space 
taken  out  by  the  cuts  before  the  tool  was  moved ;  B  B 
represents  the  first  cut  taken  after  it  was  moved  ;  c  is  the 
point  to  which  the  cut  B  is  supposed  (for  the  purpose  of 
this  illustration)  to  have  travelled. 

The  tool  used  having  been  a  little  less  than  one-half  the 
proper  width  of  the  space  of  the  thread,  it  becomes  evident 
that  the  thread  will  be  left  with  rather  more  than  its 
proper  thickness,  which  is  done  to  allow  finishing  cuts  to 
be  taken  upon  its  sides,  for  which  purpose  the  side  tool 
(given  in  Fig.  36)  is  brought  into  requisition,  care  being 
taken  that  it  be  placed  true,  so  as  to  cut  both  sides  of  the 
thread  of  an  equal  angle  to  the  centre  line  of  the  screw. 

In  cutting  V  threads  of  a  coarse  pitch,  the  tool  may  be 
made  less  in  width  than  the  required  space  between  the 
threads  demands,  so  that  it  may  be  moved  a  little  laterally 
in  order  to  hike  a  cut  off  one  side  of  the  thread  only  at  a 
time,  by  which  means  a  heavier  cut  may  be  taken  with 
less  liability  for  the  tool  to  spring  in  ;  but  the  finishing 
cut  is  better  if  taken  by  a  tool  of  the  full  width  or  shape 
of  the  thread. 

The  most  accurate  method  of  cutting  small  V  threads 
8 


8G 


COMPLETE  PRACTICAL    MACHINIST. 


is  to  use  a  stout  chaser  fastened  in  the  tool  post,  and  then 
feed  it  with  the  screw-cutting  gear  of  the  lathe,  the  same 
as  with  a  common  screw-cutting  tool.  Such  a  chattr 
should  be  made  hollow  in  the  length  of  the  tooth,  possess 
a  minimum  of  top  rake,  and  be  placed  to  cut  at  the  centre 
of  the  work ;  and  it  should  be  so  placed  in  the  tool  post 
that  the  teeth  stand  exactly  parallel  to  the  line  of  the  cut 

Fig  78. 


Fig.  78  represents  a  tool  for  cutting  an  outside  V  thread 
in  brass  work.  When,  however,  the  tool  point  must,  of 
necessity,  stand  far  out  from  the  tool  post,  it  must  be  given 
negative  top  rake,  to  make  it  cut  smoothly  and  prevent 
its  jarring.  To  adapt  this  tool  to  cutting  V  threads  on  iron, 
it  is  only  necessary  to  give  it  top  rake. 


Fig.  79. 


Fig.  79  represents  a  very  stout  tool,  adapted  to  cutting 
coarse  square  threads  on  wrought-iron  or  steel.  For  cutting 
square  threads  on  brass  work,  the  tool  shown  in  Fig.  80 
should  be  used. 

Fig.  80. 


SCREWOUTTING   TOOLS. 


87 


Fig.  81  represents  a  single  pointed  tool,  for  cutting  an 
internal  thread,  and  it  is  obvious  that  in  order  that  it  may 
cut  a  thread  of  cor- 
rect shape,  it  is 
necessary  to  grind 
the  V  to  a  gauge, 
to  set  it  so  that 
each  cutting  edge 
shall  stand  at  an 
equal  degree  of 
angle  to  the  work 
axis,  and  also  that 
the  cutting  edges 
shall  stand  level 
with  the  centre  of 
the  work  or  line  of 
lathe  centres. 

There  are  three 
different  shapes  of 
V  threads  in  use  in  the  United  States,  viz.:  first,  the 

Fig.  82. 


sharp  V  thread,  shown  in  Fig.  82,  in  which  the  thread 


38 


COMPLETE  PRACTICAL  MACHINIST. 


sides  meet  in  a  point  both  at  the  top  and  bottom,  and  these 
sides  are  at  an  angle  of  60  degrees  to  one  another.  Second, 
the  United  States  standard,  whose  form  is  shown  in  Fig. 

83,    which    corre- 

Fig.  83.  spends  in  shape  to 

the  above  thread, 
with  one-eighth  of 
the  top  cut  off,  and 
one-eighth  of  the 
bottom  filled  in  so 
as  to  leave  a  flat 
place  at  the  top 
=™  and  bottom  of  the 
:--  thread.  And  third, 
the  Whitworth 
thread  shown  in 
Fig.  84,  in  which 

the  angle  of  the  sides  of  the  thread,  one  to  the  other,  is 
55  degrees,  and  the  tops  and  bottoms  of  the  thread  are 
rounded. 

Of  these  three  threads,  the  sharp  V   or   common  V, 
as  it  is  sometimes  termed,  is  the  easiest  to  produce,  because 

Fig.  84 


if  the  angles  of  the  threading  tool  are  correct  the  top  and 
bottom  will  come  correct  of  itself,  whereas  in  the  United 
States  standard  thread  it  is  necessary  to  form  the  tool 


SCREW  CUTTING   TOOLS. 


89 


us  in  Fig.  85,  the  flat  at  the  point  requiring  great  care  to 
make  it  of  correct  width.  Either  of  these  threads  may, 
however,  be  originated  more  easily  than  the 
Fig.85.  \Vhitworth  or  English  standard  thread,  whose 
/  \  rounded  tops  and  bottoms  are  very  difficult  to 
/  \  form  correctly  and  exactly  alike.  On  this 
account  the  Whitworth  thread  is  usually  cut  by 
chasers  cut  from  a  standard  hob,  or  master 
tap,  the  hob  being  revolved  and  the  chaser 
pressed  to  it.  When,  however,  a  chaser  is  pro- 
duced, it  possesses  the  advantage  that  the  angles  of  the 
thread  sides  are  more  correct  than  is  the  case  with  single- 
pointed  tools  ground  upon  a  grinding  stone.  But  the 
common  V  and  the  United  States  standard  thread  may 
both  be  cut  by  chasers,  and  in  fact  the  United  States 
standard  thread  may  be  cut  by  a  chaser  having  the  com- 
mon V  thread  ;  all  that  is  necessary  being  to  grind  off  the 
tops  of  the  teeth,  as  in  Fig.  86,  because,  when  the  chaser 

Fig.  86. 


has  entered  the  work  far  enough  to  cut  the  flat  at  the 
thread  bottom  to  the  correct  diameter,  the  flat  at  the 
thread  top  will  be  left  of  itself. 


90 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  87  represents  a  gauge  for  testing  the  angles  of 
threading  tools  for  the  common  V,  and  for  the  United 
States  standard  threads.  It  is  not  unusual,  however,  to 

Fig.  87. 


employ  a  short  metal  gauge,  such  as  shown  in  Fig.  88, 
applying  it  direct  to  the  work,  which  will  test  if  the  tool 
has  been  correctly  set  with  relation  to  the  work.  But 
when  it  is  known  that  the  tool  is  correctly  formed,  and 
has  been  properly  set  in  the  lathe  tool  post  and  therefore 

Fig.  88. 

GAUGE. 


that  the  shape  of  the  thread  is  correct,  the  thread  diameter 
may  be  most  correctly  measured  by  callipers,  applied  as 
in  Fig.  89,  which  is  especially  advantageous  when  there 
is  at  hand  a  correct  thread  to  set  the  callipers  by. 


SCEEW-CUTT1NO  TOOLS. 


91 


To  test  the  pitch  of  a  thread,  to  find  if  its  pitch  is  alike 
at  various  parts  of  the  thread  length,  gauges  such  as  at 

Fig.  89. 


G  or  G'  in  Fig.  90  may  be  employed  ;  the  work  and  the 
Fig.  90. 


gauge  being  held  up  to  the  light,  which  will  show  very 
ciearly  any  error  that  may  exist. 


92 


COMPLETE  PRACTICAL  MACHINIST. 


In  cutting  V  threads  upon  either  inside  or  outside  work, 
great  care  should  be  taken  to  grind  the  V  tool  to  the 
exact  proper  angle,  and  to  also  set  it  quite  true  in  the 
lathe ;  to  accomplish  both  of  which  results,  we  have  the  gauge 
shown  in  Fig.  91,  and  sold  at  all  tool  stores. 


The  above  cuts  show  the  various  uses  to  which   this 
gauge  can  be  applied. 

In  Fig.  1,  at  A,  is  shown  the  manner  of  gauging  the 


SCREW-CUTTING   TOOLS.  93 

angle  to  which  a  lathe  centre  should  be  turned  ;  at  B,  the 
angle  to  which  a  screw-thread  cutting  tool  should  be  ground, 
and  at  C,  the  correctness  of  the  angle  of  a  screw-thread 
already  cut. 

In  Fig.  2,  the  shaft  with  a  screw-thread  is  supposed  to 
be  held  on  the  centre  of  a  lathe.  By  applying  the  gauge 
as  shown  at  D,  or  E,  the  thread  tool  can  be  set  at  right 
angles  to  the  shaft,  and  then  fastened  in  place  by  the 
screw  in  tool  post,  thereby  avoiding  imperfect  or  leaning 
threads. 

In  Fig.  3,  the  manner  of  setting  the  tool  for  cutting 
inside  threads  is  illustrated.  The  angles  used  in  this  gauge 
are  sixty  degrees.  The  four  divisions  upon  the  gauge  of 
14,  20,  24  and  32  parts  to  the  inch  are  very  useful  in 
measuring  the  number  of  threads  to  the  inch  of  taps  and 
screws. 

The  following  parts  to  the  inch  can  be  determined  by 
them— namely,  2,  3,  4,  5,  6,  7,  8,  10,  14,  16,  20,  24  and  32. 

If  the  tool  is  not  ground  to  the  correct  V,  or  is  not  set 
true  in  the  lathe,  the  result  is,  that  the  threads  will  bear 
upon  each  other  upon  one  side,  or  a  portion  of  one  side 
only — thus  reducing  the  amount  of  wearing  surface,  and 
causing  the  threads  to  soon  become  a  loose  fit,  as  well  as 
to  be  weaker  than  they  should  be.  A  V  thread  cut  by 
a  V  tool  in  the  lathe  is  not  so  strong  as  one  cut  by  a 
chaser,  because  chasers  cut  a  thread  slightly  rounded  at 
the  top  and  bottom  ;  whereas  the  V  tool  leaves  a  sharp 
corner. 

At  the  termination  of  the  thread,  it  is  necessary  to  cut 
a  recess  as  deep  as  the  thread,  in  order  to  give  the  chaser 
clearance,  and  prevent  it  from  ripping  into  the  shoulder, 
which  would  form  the  termination  of  the  thread  in  the 
absence  of  a  recess.  It  is  a  very  common  practice  to  cut 
this  groove  or  recess  with  a  V  tool  or  graver  point,  instead 
of  with  a  round-nosed  tool,  thus  producing  a  recess  having 


94 


COMPLETE  PRACTICAL  MACHINIST. 


a  conical  instead  of  a  curved  outline :  the  result  being  to 
very  seriously  impair  the  strength  of  the  bolt,  and  cause 
it,  under  severe  strains,  to  fracture  across  the  section  of 
the  bottom  of  the  groove. 

In  a  series  of  experiments  made  a  few  years  ago,  by  the 
English  government,  upon  targets  representing  ships' 
armor,  the  bolts  were  found  to  be  unable  to  withstand  the 
shock  caused  by  the  cannon  shot  striking  the  target ;  and 
it  being  observed  that  the  fracture  nearly  always  occurred 
across  the  section  above  referred  to,  the  clearance  grooves 
were  made  with  a  hollow  curve,  which  obviated  the  defect. 

To  calculate  the  change  gear  wheels  necessary  to  cut  a 
given  pitch. of  thread  in  a  lathe: 

The  pitch  of  a  thread  is  measured  or  denominated  in 
two  ways,  first :  by  the  number  of  threads  there  are  in  one 
inch  of  the  length  of  the  screw ;  and,  second,  by  the  dis- 
tance of  one  thread  from  the  next  one.  Thus,  in  Fig.  92, 


the  thread  may  be  expressed  as  one  of  four  per  inch,  or 
as  a  thread,  having  a  pitch  of  i  inch.  For  tine  threads 
the  pitch  is  usually  given  in  the  number  of  threads  per 
inch.  What  is  called  (as  applied  to  its  screw-cutting 
wheels)  a  single  geared  lathe  is  one  in  which  the  driving 
gear  is  either  fastened  upon  and  revolves  with  the  man- 


SCREW-CUTTING   TOOLS. 


95 


dril  or  spindle  of  the  lathe,  or  else  is  driven  by  an  inter- 
mediate gear-wheel  of  such  a  size  that  the  driving  gear, 
though  not  fast  upon  the  lathe  spindle  or  mandril,  still 
makes  the  same  number  of  revolutions  per  minute  as  does 
the  mandril,  while  at  the  same  time  no  two  wheels  (on 
such  a  lathe)  of  different  diameters  run  side  by  side, 
making  an  equal  number  of  revolutions  in  a  given  time. 

Thus    in  Fig.  93  we    have  the  driving    gear    D,  and 
intermediate  wheel  I,  and  the  lead  screw   wheel  S,  the 

Fig.  93. 


arrangement  constituting  a  simple  or  single  geared  screw 
cutting  lathe. 

In  such  a  lathe  we  have  only  to  consider  the  driving 
wheel  or  gear  and  the  gear  upon  the  feed  screw  of  the 
lathe,  the  others  or  intermediate  wheels  having  no  effect 
or  influence  (upon  the  thread  to  be  cut)  other  than  to 
make  up  the  distance  between  the  driving  and  feed  screw 
gears,  and  thus  to  communicate  the  motion  of  the  one  to 
the  other.  Hence,  having  ascertained  what  sized  wheel 
is  required  for  the  driving  wheel  and  on  the  feed  screw, 


96  COMPLETE  PRACTICAL  MACHINIST. 

we  may  connect  them  together  by  any  wheel  or  wheels 
that  will  answer  irrespective  of  their  sizes. 

It  will  be  readily  perceived,  then,  that  if  the  driving 
gear  and  the  feed  screw  gear  contain  respectively  the 
same  number  of  teeth,  the  lathe  would  be  geared  to  cut  a 
thread  of  the  same  pitch  as  the  pitch  of  the  thread  on  the 
feed  screw  of  the  lathe,  because  the  feed  screw  would 
revolve  at  the  same  speed  as  the  lathe  did.  Now,  in 
exact  proportion  as  the  feed  screw  revolves,  slower  than 
does  the  lathe  spindle  or  mandril,  will  the  thread  cut  by 
the  lathe  tool  be  finer  than  that  on  the  feed  screw,  and 
vice  versa;  hence  we  have  —  whereby  to  find  the  wheels 
necessary  to  cut  a  thread  of  a  required  pitch  in  a  single 
geared  lathe  —  the  following  rule  : 

Put  down  the  pitch  of  the  lead  screw,  as  the  numerator 
of  a  fraction,  and  put  beneath  it  the  pitch  of  the  thread 
you  want  to  cut,  and  these  figures  will  represent  the  re- 
quired number  of  teeth  the  wheels  should  have. 

For  example,  the  pitch  of  a  lead  screw  is  8  threads  per 
inch,  and  we  require  to  cut  a  pitch  of  16.  Then 

Pitch  of  lead  screw  8  =  number  of  teeth  for  the  driving  gear. 

Thread  to  be  cut     16  =  No.  of  teeth  for  the  gear  on  the  lead  screw. 

Again  :  the  pitch  of  a  lead  screw  is  6,  and  we  require 
to  cut  a  thread  whose  pitch  is  24.  Then 

Pitch  of  lead  screw  6  =  number  of  teeth  for  driving  gear. 
Pitch  to  be  cut        24  =  number  of  teeth  for  lead  screw  gear. 

If  we  have  no  wheels  containing  these  respective  num- 
bers of  teeth,  we  multiply  the  fraction  by  any  number  we 
may  choose,  as  by  2,  3,  4,  5  or  6. 
Thus— 

6  12  =  number  of  teeth  for  driving  gear. 

~2¥  48  =  number  of.  teeth  for  lead  screw  gear. 


Or  —  6     v  o  _    _!§_  ==  nurober  of  teeth  for  driving  gear. 

24~  72  =  number  of  teeth  for  lead  screw  gear. 

Or  —  6  _  24  =  number  of  teeth  for  driving  gear. 

24    '  96  T  =  number  of  teeth  for  lead  screw  gear. 


SCREW-CUTTING  97 

Let  us  now  suppose  that  we  require  to  cut  a  fractional 
thread,  as,  say,  the  lead  screw  being  4  per  inch,  we  wish  to 
cut  a  pitch  of  4i  threads  per  inch,  and  all  we  have  to  do 
is  to  put  down  the  lead  screw  pitch  expressed  in  quarter 
inches  and  the  pitch  to  be  cut  in  quarter  inches.  Thus 
there  are  16  quarters  in  4  and  17  quarters  in  4}.  Hence, 
the  fraction  becomes 

16  =  number  of  teeth  for  driving  gear. 

17  =  number  of  teeth  for  lead  screw  gear. 

If  we  have  not  these  gears,  we  multiply  by  any  number 
as  before.  Thus — 

*6  32  ==  numher  of  teeth  for  driving  gear. 

17  ~~  34  =  number  of  teeth  for  lead  screw  gear. 

Or —  16         o  48  =  number  of  teeth  for  driving  gear. 

17  ~  51  =  number  of  teeth  for  lead  screw  gear. 

Or —  16  64  =  number  of  teeth  for  driving  gear. 

17  68  =  number  of  teeth  for  lead  screw  gear. 

The  term  Compound  or  double  geared,  as  applied  to  the 
screw-cutting  gear  of  a  lathe,  means  that  there  exists, 
between  the  gear  wheel  which  is  fastened  to,  and  revolves 
with,  the  lathe  spindle,  and  the  feed  screw,  two  gear 
wheels  of  different  diameters  and  revolving  side  by  side, 
at  the  same  number  of  revolutions,  by  reason  of  being 
fixed  upon  the  same  sleeve  or  axis.  The  object  of  this 
arrangement  is  to  make,  between  the  speed  at  which  the 
lathe  mandril  or  spindle  will  run,  and  the  speed  or  rev- 
olutions at  which  the  feed  screw  will  run,  a  greater 
amount  of  difference  than  is  possible  in  a  single  geared 
lathe,  and  thus  to  be  able  to  cut  threads  of  a  coarser  pitch 
than  could  be  cut  in  the  latter.  This  is  usually  accom- 
plished by  providing  two  intermediate  wheels  of  different 
diameters,  both  being  held  by  a  feather  to  a  sleeve  re- 
volving upon  an  adjustable  pin  provided  for  the  purpose. 
Thus  Fig.  94  represents  an  arrangement  of  compounded 
gear,  in  which  A  is  the  driving  gear,  C  and  D  the  com- 
pounded pair  of  wheels  carried  on  a  stud  in  the  swing 
frame  F,  and  S  the  lead  screw  gear.  In  this  arrange- 
9 


98 


COMPLETE  PRACTICAL  MACHINIST. 


ineut,  the  driving  gear  A  is  fixed  and  cannot  readily  be 
taken  off;  hence  it  must  in  many  cases  be  taken  into 
account  in  finding  the  gears,  all  the  changes  being  made 
in  the  wheels  C,  D  and  S. 

Sometimes,  however,  only  the  wheel  upon  the  lead 
screw  need  be  changed,  since  a  wide  range  of  pitch  may 
be  obtained  without  disturbing  any  other  wheel.  Suppose, 
for  example,  that  the  driving  gear  or  gear  on  the  latho 
mandril  or  spindle  has  32  teeth,  and  that  the  compounded 
pair  is  arranged  to  reduce  the  motion  one-half,  and  tho 
effect  is  the  same  as  if  the  driving  gear  had  16  teeth  and 
there  was  no  compound  gears  employed. 

Fig.  94. 


To  find  the  number  of  teeth  in  the  wheel  required  to  be 
placed  on  the  feed  screw,  we  have  the  following  rule: 

Divide  the  pitch  to  be  cut  by  the  pitch  of  the  feed 
screw,  and  the  product  will  be  the  proportional  number. 
Then  multiply  the  number  of  teeth  on  the  lathe  mandril 
gear  by  the  number  of  teeth  on  the  smallest  gear  of  t  he  com- 


SCREW-CUTTING.  99 

pounded  pair,  and  the  product  by  the  proportional  num- 
ber, and  divide  the  last  product  by  the  number  of  teeth 
in  the  largest  wheel  of  the  compounded  pair,  and  the 
product  is  the  number  of  teeth  for  the  wheel  on  the  feed 
screw. 

Suppose,  for  example,  the  gear  on  the  lathe  mandril 
contains  40  teeth  running  into  the  largest  of  the  com- 
pounded gears  which  contains  50  teeth,  and  that  the  smnll 
gear  of  the  compounded  pair  contains  15  teeth  ;  what 
wheel  will  be  required  for  the  feed  screw — its  pitch  being 
2,  and  the  thread  requiring  to  be  cut  being  20? 

Pi;ch  Pitch  or  Proportional 

required.  feed  screw.  number. 

20      -4-      2      =      10 
Then— 

Mandril  Small  com-       Proportional      Large  corn- 

gear  teeth.         pound  gear.          number.          pound  gear. 

40  X  15  X  10  H-  50  =  120  =  the  num- 
ber of  teeth  required  upon  the  wheel  for  the  feed  screw. 
In  the  above  example,  however,  all  the  necessary  wheels 
except  one  are  given  ;  and  since  it  is  often  required  to 
find  the  necessary  sizes  of  two  of  the  wheels,  the  following 
rule  may  be  used  : 

Divide  the  number  of  threads  you  wish  to  cut  by  the 
pitch  of  the  feed  screw,  and  multiply  the  quotient  by  the 
number  of  teeth  on  one  of  the  driving  wheels,  and  the 
product  by  the  number  of  teeth  on  the  other  of  the  driving 
wheels ;  then  any  divisor  that  leaves  no  remainder  to  the 
last  product  is  the  number  of  teeth  for  one  of  the  wheels 
driven,  and  the  quotient  is  the  number  of  teeth  for  the 
other  wheel  driven. 

[In  this  rule  the  term  "wheel  driven"  means  a  wheel 
which  has  motion  imparted  to  it,  while  its  teeth  do  not 
drive  or  revolve  any  other  wheel ;  hence  the  large  wheel  of 
the  compounded  pair  is  one  of  the  wheels  driven,  while  the 
wheel  on  the  feed  screw  is  the  other  of  the  wheels  driven.] 

Example.  It  is  required  to  cut  20  threads  to  the  inch, 
the  pitch  of  the  feed  screw  being  2,  one  of  the  driving 
wheels  contains  40  teeth  and  the  other  15 : 


100 


COMPLETE  PRACTICAL  MACHINIST. 


Pitch  required  Pitch  of  Teeth  in  one  Teeth  in  other 

to  be  cut.  feed  screw.         driving  wheel.  driving  wheel. 


20      -=-2      X      40      X      15      =      6000. 
Then,  6000  -h  50  =  120;  and  hence  one  of  the  gears  will 
require  to  contain  50  and  the  other  120  teeth  ;  if  we  have 
not  two  of  such  wheels,  we  may  divide  by  some  other 
number  instead  of  50. 

Thus:  6000  -=-  60  =  100;  and  the  wheels  will  re- 
quire to  have,  respectively,  60  and  100  teeth. 

If  there  are  no  wheels  on  the  lathe  we  proceed  as  fol- 
lows : 

Divide  the  pitch  required  by  the  pitch  of  the  feed  screw ; 
the  quotient  is  the  proportion  between  the  revolutions  of 
the  first  driving  gear  and  the  feed  screw  gear. 

Example.  Required  the  gears  to  cut  a  pitch  of  20,  the 
feed  screw  pitcli  being  4  ;  here  20  -f-  4  =  5  ;  that  is  to  say, 
the  feed  screw  must  revolve  five  times  as  slowly  as  the  first 
driving  gear;  we  now  find  two  numbers  which,  multiplied 
together,  make  five:  as  2i  X  2  =  5;  hence  one  pair  of  wheels 
must  be  geared  2 1  to  1  and  the  other  pair  2  to  1,  the 
small  wheel  of  each  pair  being  used  as  drivers,  because 
the  thread  required  is  finer  than  the  feed  screw. 

Fig.  95  represents  an  arrangement  of  compound  gears 


Fig.  95. 


SCREW-CUTTISQ. 


101 


common  in  small  American  lathes.  A  is  the  actual  driv- 
ing gear,  B  an  intermediate,  and  C  D  are  the  compound 
pair.  In  this  case  the  wheels  A,  B  and  C  are  fixed  and 

Fig.  96. 


102        COMPETE 'PRACTICAL  MACHINIST. 

cannot  be  changed  ;  hence  all  we  have  to  consider  is  the 
sizes  of  D,  and  of  the  lead  screw  gear  S.  Suppose,  now, 
that  the  wheel  D  has  the  same  number  of  teeth  as  wheel 
C,  and  we  may  neglect  C  and  calculate  the  change  gears 
the  same  as  if  D  was  on  the  lathe  spindle,  and  A,  B  and 
C  were  not  used.  But  in  a  majority  of  cases  D  will 
have  to  be  changed  as  well  as  S,  and  then  the  size  of  C 
must  be  taken  into  account.  In  this  case  we  proceed 
precisely  as  before,  finding  the  proportion  that  must  exist 
between  the  revolution  of  the  mandril  and  of  the  lead 
screw,  and  arranging  the  wheels  accordingly. 

The  wheels  necessary  to  cut  a  left-hand  thread  are 
obviously  the  same  as  those  necessary  for  a  right-hand 
one  of  the  same  pitch. 

The  pitches  of  threads  used  in  France  are  given  in 
terms  of  the  centimeter,  and  the  method  of  finding  the 
necessary  change  gears  are  as  follows : 

An  inch  equals  f §J  of  a  centimeter,  or  in  other  words 
1  inch  bears  the  same  proportion  to  a  centimeter  as  254 
does  to  100,  and  we  may  take  the  fraction  ?^J  and  re- 
duce it  by  any  number  that  will  divide  both  terms  of 
the  fraction  without  leaving  a  remainder.  Thus  f§g 
-  2  =  W- 

If  then  we  take  a  pair  of  gears,  having  respectively  127 
and  50  teeth,  they  will  form  a  compound  pair  that  will 
enable  the  cutting  of  threads  in  terms  of  the  centimeter 
instead  of  in  terms  of  the  inch.  It  is  obvious  that  as  a 
centimeter  is  more  than  an  inch,  this  compound  pair  must 
be  used  to  reduce  the  revolutions  of  the  lead  screw,  or 
arranged  as  in  Fig.  96,  the  changes  of  wheels  for  any 
given  number  of  threads  per  centimeter  being  made  at  D 
and  at  S  only. 

TO   CUT   A    DOUBLE   THREAD. 

A  double  thread  is  one  formed  by  two  spiral  grooves 
instead  of  one.  Thus  in  Fig.  97  we  have  one  spiral  at  A 


SCREW-CUTTING. 


103 


and  another  at  B,  the  latter  being  carried  as  far  as  C 
only.  The  true  pitch  of  the  thread  is  in  this  case  the 
pitch  of  one  spiral,  or  twice  the  apparent  pitch. 

To  cut  such  a  thread,  we  arrange  the  change  wheels  for 
the  true  pitch  A  and  cut  that  spiral  first.  Then  we  stop 
the  lathe  and  taking  off  the  lead  screw  gear  of  the  change 
wheels,  and  move  the  lathe  so  that  the  driving  gear 
makes  one-half  revolution  ;  then  we  put  the  lead  screw 
gear  back  and  the  lathe  is  adjusted  to  cut  the  second 
thread. 

Suppose,  for  example,  that  the  wheels  used  are  a  36 


and  a  72.  as  in  Fig.  98 ;  then  we  make  a  mark  atS  on  the 
driving  gear,  and  a  corresponding  one  on  the  lead  screw 
gear,  and  then  take  the  lathe  off  the  lead  screw;  we  then 
count  18  teeth  on  the  driving  gear,  make  a  mark  on  the 
eighteenth  tooth  and  pull  the  lathe  round  so  that  the 
mark  on  the  lead  screw  gear  will  engage  with  the  eigh- 
teenth tooth  on  the  lead  screw  gear. 

For  a  treble  screw  we  would  require  to  divide  the  driv- 
ing gear  by  three,  thus,  36  -i-  3  =  12,  and  we  must 
count  12  teeth  from  S  and  proceed  as  before  ;  for  a  quad- 
ruple thread  we  divide  the  36  by  4  and  proceed  as  before, 
and  so  on. 


104          COMPLETE  PRACTICAL  MACHINIST. 
Fig.  98. 


LEAD -SCREW    GEAR 
72    TEETH 


HAND    CHASING. 


To  cut  a  screw  by  baud  in  the  lathe  we  proceed  as  fol- 
lows: The  work  is  turned  up  to  the  required  size,  and 
then  on  the  outside  of  the  work  we  employ'  the  V  tool 


SCREW-CUTTING   TOOLS. 


105 


shown  in  Fig.  99  ;  which  tool  is  made  of  a  piece  of  steel 
about  fV  or  i  inch  thick,  and  £  inch  deep,  the  holding  end 
being  fitted  into  a  handle.  The  point  A  is  the  cutting 
edge;  the  point  B  being  formed  so  that  when  the  tool  is 
pressed  firmly  to  the  lathe  rest  face,  it  will  not  slip  but 
will  hold  fast ;  and  the  top  face  being  given  a  little  top  rake 
when  the  tool  is  used  upon  wrought-iron  or  steel,  whereas 
negative  top  rake  is  necessary  for  use  upon  brass  work. 

The  end  of  the  work  from  which  the  thread  starts  should 
be  filed  smooth,  and  all  the  turning  tool  marks  effaced 
before  the  attempt  is  made  to  start  the  thread,  because  the 
"lightest  obstruction  will  cause  the  motion  of  the  starting 
tool  to  be  irregular,  and  this  will  prevent  the  chaser  from 

Fig.  99. 


SIDE  VIEW 


TOP  VIEW 

readily  picking  up  the  thread,  which  is  a  delicate  opera- 
tion, requiring  great  care,  even  from  an  experienced  hand. 

When  the  thread  starts  from  the  end  of  the  work,  it  is 
necessary  to  round  off  the  corner,  because  (assuming  the 
thread  to  be  a  right  hand  one)  it  is  easier  to  start  the 
thread  at  the  right  hand  end,  and  carry  it  forward  with 
the  chaser,  than  it  is  to  start  it  at  the  left  hand  end  and 
carry  it  back  to  the  right.  Similarly  for  a  left  hand  thread, 
it  must  be  started  at  the  left  hand  end,  and  carried  to  the 
right,  and  in  this  case  the  corner  may  be  rounded  off, 
either  before  or  after  chasing  the  thread  at  pleasure. 

To  start  the  thread,  the  lathe  should  be  run  at  a  fast 
ppeed ;  and  the  heel  of  the  tool  being  pressed  firmly  to  the 


106  COMPLETE  PRACTICAL  MACHINIST. 

face  of  the  lathe-rest,  the  point  of  the  V  of  the  tool  being 
brought  firmly  into,  contact  with  the  work,  while  the  handle 
of  the  tool  must  be  twisted  from  right  to  left  at  the  same 
time  as  it  is  moved  bodily  from  the  left  to  the  right.  It  is 
the  relative  quickness  with  which  these  combined  movements 
are  performed  which  will  determine  the  pitch  of  the  thread. 
The  results  of  these  combined  movements  will  be  a  fine 
groove  cut  upon  the  work,  and  of  the  same  distance  from 
one  groove  to  the  next  as  the  distance  of  one  tooth  of  the 
chaser  to  the  next.  If  the  spiral  groove  so  cut  is  only  the 
proper  pitch  at  one  part,  as,  say,  at  the  starting  end,  the 
chaser  may  be  so  held  and  applied  as  only  to  touch  that 
end,  when  it  will  readily  find  the  groove  if  applied  lightly 
to  it.  Then  several  light  cuts  may  be  taken  off  that  end, 
before  attempting  to  carry  the  thread  along. 

The  chaser  is  applied  by  being  pressed  lightly  against 
the  work,  and  moved  along  the  lathe-rest  at  as  nearly  the 
proper  speed  as  can  be  judged.  The  chaser  should  be 
held  so  that  its  hind  teeth  press  hardest  against  the  work, 
which  will  keep  them  in  the  starting  groove  and  act  as  a 
guide  to  the  front  teeth,  while  they  extend  Ihe  groove, 
carrying  the  thread  forward  to  the  required  distance  on 
the  work. 

The  reason  for  running  the  lathe  at  a  comparatively 
fast  speed  is,  that  the  tool  is  then  less  likely  to  be  checked 
in  its  movement  by  a  seam  or  hard  place  in  the  metal  of 
the  bolt,  and  that,  even  if  the  metal  is  soft  and  uniform 
in  its  texture,  it  is  easier  to  move  the  tool  at  a  regular 
speed  than  it  would  be  if  the  lathe  ran  comparatively 
slowly. 

If  the  tool  is  moved  irregularly  or  becomes  checked  in 
its  forward  movement,  the  thread  will  become  "drunken/* 
that  is,  it  will  not  move  forward  at  a  uniform  speed  ;  and 
if  the  thread  is  drunken  when  it  is  started,  the  chaser  will 
not  only  fail  to  rectify  it,  but,  if  the  drunken  part  occurs 
in  a  part  of  the  iron  either  harder  or  softer  than  the  rest 


SOU  K  W-  CUTTING.  107 

of  the  metal,  the  thread  will  become  more  drunken  as  the 
chaser  proceeds.  It  is  preferable,  therefore,  if  the  thread 
is  not  started  truly,  to  try  again,  and,  if  there  is  not  suffi- 
cient metal  to  permit  of  the  starting  groove  first  struck 
being  turned  out,  to  make  another  further  along  the  bolt. 
It  takes  much  time  and  patience  to  learn  to  strike  the 
requisite  pitch  at  the  first  trial ;  and  it  is  therefore  requi- 
site for  a  beginner  to  leave  the  end  of  the  work  larger  in 
diameter  than  the  required  finished  size,  so  as  to  have 
metal  sufficient  to  turn  out  the  first  few  starting  grooves, 
should  they  not  be  true  or  of  the  correct  pitch.  If,  how- 
ever, a  correct  starting  groove  is  struck  at  the  first  attempt, 
the  chaser  may  be  applied  sufficiently  to  cut  the  thread 
down  to  and  along  the  body  of  the  bolt;  then  the  projec- 
tion may  be  turned  down  with  the  graver  to  the  required 
size,  and  the  chasing  proceeded  with. 

After  the  thread  is  struck,  and  before  the  chaser  is  ap- 
plied to  it,  the  top  face  of  the  rest  should  be  lightly  filed 
to  remove  any  burrs  which  may  have  been  made  by  the 
heel  of  the  V  tool  or  graver;  or  such  burrs,  by  checking 
the  even  movement  of  the  chaser,  will  cause  it  to  make 
the  thread  drunken.  Where  the  length  of  the  thread  ter- 
minates, a  hollow  curved  groove  should  be  cut,  its  depth 
being  even  with  the  bottom  of  the  thread  ;  the  object  of 
this  groove  is  to  give  the  chaser  clearance,  and  to  enable 
you  to  cut  the  thread  parallel  from  end  to  end  and  not  to 
leave  the  last  thread  or  two  larger  in  diameter  than  the 
rest.  Another  object  is  to  prevent  the  front  tooth  of  the 
chaser  from  ripping  in  and  breaking  off,  as  it  would  be 
very  apt  to  do  in  the  absence  of  the  groove. 

TO   MAKE   A    CHASER. 

Chasers  are  cut  frnm  a  hub,  that  is  to  say,  a  cutter 
formed  by  cutting  a  thread  upon  a  piece  of  round  steel, 
and  then  forming  cutting  edges  by  cutting  a  series  of 
grooves  along  the  length  of  the  hub.  These  grooves 


108  COMPLETE  PRACTICAL  MACHINIST. 

should  be  V-shaped,  the  cutting  side  of  the  groove  having 
its  face  pointing  radially  towards  the  centre  of  the  hub. 
Hubs  should  be  tempered  to  a  brown  color.  A  chaser  is 
made  from  a  piece  of  flat  steel  whose  width  and  thickness 
increases  with  the  pitch  of  the  thread  ;  the  following  pro- 
portions will,  however,  be  found  correct: 


NUMBER  OF  THREADS 
PER  INCH. 

NUMBER  OF  TEETH 
IN  THE  CHASER. 

THICKNESS  OF  THE 
CHASER. 

24  to  20 
18  to  14 
12  to   8 
6  to   4 

12  to  14 
10 
9  to   6 
7  to   6 

i  inch. 

5     " 

'f    " 

The  end  face  of  the  chaser  should  be  filed  level  and  at 
an  angle  with  both  the  top  face  and  the  front  edge  of  the 
steel,  both  top  and  bottom  rounded  off  so  that  at  the  top 
it  will  not  dig  into  the  shoulder  at  the  end  of  the  thread, 
and  at  the  bottom  it  will  not  strike  against  a  burr  or  other 
obstruction  or  the  face  of  the  lathe  rest,  and  thus  be  re- 
tarded in  its  forward  movement  while  being  cut.  The 
hub  is  then  driven  in  the  lathe  between  the  centres,  the 
chaser  being  held  in  a  handle  sufficiently  long  to  enable 
the  operator  to  hold  it  with  one  hand,  and  press  the 
shoulder  against  the  end  so  as  to  force  the  end  of  the  chaser 
against  the  hub,  which  will  of  itself  carry  the  chaser  along 
the  rest.  During  the  operation  of  cutting  the  chaser  by 
the  hub,  the  former  will  be  upside  down,  its  cutting  face 
(when  finished)  being  that  which  during  this  operation  is 
resting  on  the  face  of  the  lathe-rest,  which  latter  should  be 
placed  a  short  distance  from,  and  not  close  up  to  the  hub. 
After  the  chaser  has  passed  once  down  the  hub,  special 
attention  should  be  paid  as  to  whether  the  front  tooth  will 
become  a  full  one  ;  if  not,  the  marks  cut  by  the  hub  should 
be  filed  out  again,  and  a  new  trial  essayed.  It  must  be 
borne  in  mind  that,  the  chaser  being  held  upside  down, 
the  back  tooth,  while  cutting  the  chaser,  becomes  the  front 


SCREW-CUTTING   TOOLS. 


109 


one  when  the  chaser  is  reversed  and  ready  for  use.  The 
hub  should  be  run  at  a  comparatively  slow  speed,  and 
kept  freely  supplied  with  oil,  it  being  an  expensive  tool 
to  make,  and  this  method  of  using  preserves  it.  In  Fig. 
100,  A  is  a  chaser  whose  front  tooth  is  not  a  full  one;  B  is 
a  chaser  with  a  full  front  tooth;  and  it  is  obvious  that  the 
half  tooth  at  A  would  break. 

Fig.  100. 


A 

vvvvx 

1 

KAAA 

The  cutting  operation  of  the  hub  upon  the  chaser  is 
continued  until  the  thread  upon  the  latter  is  cut  full,  when 
it  is  taken  to  the  vise  and  filed  as  follows : 

The  top  and  bottom  edges  immediately  behind  the  front 
tooth  are  rounded  off  as  already  directed.  Then  along  the 
bottom  of  the  chaser  the  teeth  are  rounded  off  to  prevent 
them  from  catching  against  any  burr  on  the  face  of  the 
lathe  rest. 

An  outside  chaser  for  cutting  wrought-iron  by  hand 
should  be  made  hollow  in  the  length  of  the  tooth,  and 
have  top  rake,  to  enable  it  to  cut  easily;  for  the  strain 
required  to  bend  the  shaving  out  of  the  straight  line  will 
hold  the  teeth  to  their  cut.  Top  rake  may,  in  fact,  be 
applied  to  such  an  extent  that  the  chaser  will  cut  well  of 
itself  without  having  any  force  applied  to  it  except  suffi- 
cient to  keep  it  level,  but  if  made  so  keen,  it  soon  loses  its 
edge  and  is  very  apt  to  break. 

For  use  on  cast-iron  or  brass,  an  outside  chaser  must  be 
10 


no 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  101 


made  less  keen  by  giving  the  top  face  of  the  teeth  no  rake, 
or  else  negative  top  rake  and  cutting  the  teeth  less  hollow 
in  their  lengths.  The  latter  object  is  obtained  by  moving 
the  handle,  in  which  the  chaser  is  fixed,  up  and  down 
while  the  hub  is  cutting  it. 

The  lathe  rest  should  be  so  adjusted  that  the  chaser 
teeth  cut  above  the  horizontal  centre  of  the  work.  The 
teeth  of  the  chaser  should  fit  the  thread  on  the  bolt  along 
all  their  length  when  the  body  of  the  chaser  is  horizontal, 
and  then  the  least  raising  of 
the  handle  end  of  the  chaser 
will  present  the  teeth  to  the 
work  in  position  to  cut,  while 
the  teeth  behind  the  cutting 
edge  will  fit  the  thread  being 
cut,  sufficiently  close  to  form  a 
guide  to  steady  the  chaser. 
This  method  of  using  will  not 
only  keep  the  thread  true,  but 
will  preserve  the  cutting  edge 
of  the  chaser.  If  a  chaser  has 
top  rake,  and  the  handle  end 

is  held  too  high  and  so  that  the  back  of  the  teeth  are  clear 
of  the  thread,  it  will  cut  a  thread  deeper  than  are  its  own 
teeth  ;  if,  on  the  other  hand,  the  top  face  is  beveled  off, 
and  the  handle  is  held  too  high,  it  will  cut  a  thread  shal- 
lower than  the  chaser  teeth. 

Fig.  101  represents  a  chaser  in  use  on  wrought-iron.  It 
will  be  observed  that  the  tops  of  the  teeth  do  not  stand  at 
a  right  angle  to  the  side  edges  of  the  chaser;  the  object 
of  this  is  to  make  the  front  edge  of  the  chaser  clear  the 
driver  or  dog  driving  the  work. 

An  inside  chaser,  that  is,  one  for  cutting  threads  in  a 
hole  or  bore,  should  be,  if  to  be  used  for  cutting  a  right- 
handed  thread,  cut  off  a  left-handed  hub,  otherwise  the 
chaser  will  have  its  thread  sloping  in  the  opposite  direc- 
tion to  the  thread  to  be  cut.  This  is  shown  as  follows : 


SCREW-GUTTING   TOOLS. 


Ill 


In  Fig.  102  is  shown  a  top  view  of  an  inside  chaser 
applied  to  a  piece  of  work  represented  to  be  cut  in  half 
so  as  to  expose  the  chaser  to  view.     Now  in  order  to  en- 
Fig.  102. 


able  the  cutting  of  the  chaser  from  the  hob  it  must  be  bent 
as  shown  in  Fig.  103,  in  which  C  represents  the  chaser, 
R  the  lathe  band  rest  and  H  the  hob. 


112 


COMPLETE  PRACTICAL  MACHINIST. 


An  end  view  is  shown  in  Fig.  104,  and  it  is  seen  that 
the  chaser  teeth  will  slant  in  the  direction  of  the  dotted 
Fig.  104. 


liue  B  B.  But  when  we  come  to  straighten  the  chaser 
and  turn  it  around  as  we  must,  to  apply  it  to  the  work,  we 
shall  find  that  the  teeth  slant  in  the  wrong  direction,  as 


.SCREW-CUTTING   TOOLS.  113 

is  shown  in  Fig.  105,  in  which  the  dotted  line  B  B 
corresponds  to  the  same  line  in  Fig.  104  ;  whereas  the  teeth 
should  slant  in  the  direction  of  the  dotted  line  A  A, 
in  order  to  match  the  threads  in  the  work. 

An  inside  chaser  cut  from  a  hob  having  a  right-hand 
thread  can  be  used  to  cut  a  right-hand  one,  but  only  by 
so  tilting  the  teeth  that  only  their  edges  have  contact  with 
the  bore  of  the  work.  Now  since  an  inside  chaser  would 
be  too  keen  and  would  hence  rip  into  the  work  if  it  pos- 
sessed any  top  rake,  and  since  it  usually  requires  to  have 
a  slight  degree  of  negative  top  rake,  tilting  it  causes  it  to 
cut  a  thread  shallower  than  the  depth  of  its  own  teeth. 

In  the  absence  of  a  hob  an  inside  chaser  may  be  cut  by 
a  piece  of  wrought-iron  having  a  hole  and  a  slot  cut  in 
the  side  of  the  hole.  If  then  the  chaser  is  forged  straight 
ready  for  use  and  fastened  into  the  slot,  and  the  hole  is 
tapped  out,  the  tap  will  at  the  same  time  cut  the  teeth 
upon  the  chaser,  a  right-hand  tap  cutting  a  right-hand 
chaser.  In  adopting  this  plan,  however,  it  is  proper  to 
use  a  tap  of  a  diameter  large  in  proportion  to  the  pitch  of 
the  thread,  otherwise  the  teeth  of  the  chaser  will  be  hol- 
lowed too  much  in  the  direction  of  their  length,  and  will 
in  consequence  jar  or  chatter  when  cutting,  especially 
when  in  use  upon  long  bores,  in  which  cases  the  teeth  cut 
at  a  long  distance  out  from  the  lathe  rest.  It  is  a  good 
1  Ian  to  bore  a  quarter-inch  hole  in  the  top  face  of  the 
lathe  rest,  and  to  insert  therein  a  small  pin,  against  which 
the  edge  of  the  chaser  opposite  to  the  teeth  may  be  pressed, 
so  that  the  pin  will  act  as  a  fulcrum  to  force  the  teeth  into 
their  cut. 

Inside  threads  are  started  by  pressing  the  teeth  lightly 
against  the  bore  of  the  work,  and  moving  the  chaser  for- 
ward at  about  the  requisite  speed.  The  corner  of  the  bore 
of  the  work  should  be  slightly  rounded  off  (as  should 
also  the  corner  on  the  end  of  work  to  be  chased  with  an 
outside  thread)  to  prevent  the  chaser  teeth  from  catching 
ngainst  it. 
10- 


114  COMPLETE  PRACTICAL  MACHINIST. 

Either  an  inside  or  an  outside  chaser  may  be  employed 
to  cut  a  double  or  even  a  triple  thread.  A  double  thread 
is  one  in  which  the  distance  from  one  thread  to  the  next 
is  only  one-half  the  actual  pitch  of  the  thread.  Thus  sup- 
posing a  thread  of  five  to  an  inch  to  be  started  in  a  screw- 
cutting  lathe,  and  that  the  tool  point  is  then  moved  later- 
ally so  as  to  cut  another  groove  between  the  grooves  first 
cut,  there  will  be  two  threads  each  of  a  pitch  of  five  to  an 
•  inch,  and  yet  the  distance  from  one  thread  to  the  next 
will  only  be  one-tenth  of  an  inch,  hence  a  chaser  of  the 
latter  pitch  may  be  used  to  cut  up  the  two  threads,  thus 
producing  a  double  thread  whose  actual  is  twice  that  of. 
its  apparent  pitch. 

Beginners  should  always  stop  the  lathe  and  examine 
a  single  inside  thread  as  soon  as  it  is  struck,  for  it  is  an 
easy  matter  to  cut  a  double  female  thread  in  consequence 
of  moving  the  chaser  too  fast,  nor  will  the  error  be  dis- 
covered until  the  thread  is  finished. 

Double  outside  or  male  threads,  to  be  cut  by  hand,  can 
be  most  easily  started  by  the  chaser,  moving  it  twice  as 
fast  as  would  be  required  for  a  single  thread,  rounding  off 
the  corner  of  the  bolt  end,  and  taking  care  to  cut  princi- 
pally with  the  hindermost  teeth. 

The  proper  temper  for  the  teeth  is  a  deep  brown,  or,  for 
unusually  hard  metal,  a  straw  color.  For  chasing  wrought- 
iron,  the  lathe  may  be  run  so  that  the  teeth  will  perform 
about  40  feet,  for  steel  about  30  feet,  for  cast-iron  50  feet, 
and  for  brass  about  80  feet,  of  cutting  per  minute. 

The  quickest  way  to  cut  a  number  of  threads  upon  bolts 
requiring  to  have  a  true  thread  and  of  an  ordinarily  good 
fit,  is  to  take  about  two  good  cuts  with  a  screw  tool  in  the 
lathe,  and  then  fastening  a  solid  die  in  the  vise  to  screw 
the  bolt  through  the  solid  die  by  the  aid  of  a  wrench  on 
the  bolt  head.  The  cuts  taken  in  the  lathe  will  make  the 
bolt  enter  the  die  easily  and  true,  while  the  die  will  insure 
Correctness  of  size  in  the  thread;  bolts  threaded  thus  may 


SCREW- CUTTING   TOOLS.  115 

be  screwed  at  least  four  times  as  quick  us  by  finishing 
them  entirely  in  the  lathe. 

In  making  a  hob  or  master-tap  for  use  to  tap  solid  dies, 
cut  in  it  as  many  flutes  as  will  leave  sufficient  strength  to 
the  teeth,  and  let  the  number  be  an  odd  one. 

To  clean  rusted  threads  ou  studs  in  their  places,  or  to 
remove  burrs  from  them,  make  a  steel  nut  and  file  two 
slots  through  it  after  the  manner  of  a  solid  die  ;  and,  after 
tempering  it  to  a  light  straw  color,  screw  it  along  the 
threads  requiring  to  be  cleaned,  applying  a  little  oil.  It 
must  not  be  forgotten,  that  as  steel  shrinks  in  hardening, 
the  tap  used  for  this  purpose  should  be  a  little  above  the 
standard  size,  or  else  worked  sufficiently  in  the  nut  to  cut 
it  out  larger  than  the  normal  size. 


CHAPTER   V. 


LATHE   DOGS,    CARRIERS   OR    DRIVERS. 

The  simplest    form  of  carrier   or  dog  for  lathe  work 
is    the    bent-tailed    dog,   shown 
Fig.  106.  in  Fig.  106,  its  bent   end    pro- 

jecting into  a  slot  in  the  face 
plate.  It  is  objectionable,  how- 
ever, inasmuch  as  it  is  driven 
at  the  leverage  A  from  the  work 
it  exerts  a  strain  tending  to 
bend  it.  This  may  be  to  some 
extent  obviated  by  leaving  its 
end  straight  and  driving  it  with 
a  pin  projecting  from  the  face 
plate,  as  in  Fig.  107.  The  driv- 
ing strain  may  be  further  equal- 
ized by  employing  two  pins,  as 
in  Fig.  108,  but  it  is  difficult  to 
bring  both  the  driving  pins  to 
bear  upon  the  dog.  This  may, 

however,  be  accomplished  by  the  means  shown  in  Fig. 
109,  which  represents  a  face  plate  with  the  two  pins 
thread  into  nuts  in  a  T  groove  provided  on  the  face 
plate.  The  pins  are  screwed  up  moderately  tight  upon 
the  work  and  the  cut  is  put  on.  If  one  pin  only  meets 
the  dog  it  will  slip  in  the  groove  and  cause  the  other  pin 
also  to  drive,  and  both  pins  may  then  be  screwed  firmly 
home  to  their  nuts. 

A  more  perfect  method  of  equalizing  the  driving  strain 
is  by  means  of  the  Clements  driver,  which  is  self-adjus:ing 
(116; 


LATHE  DOGS,   CARRIERS  OR  DRIVERS.       117 
Fig.  107. 


118 


COMPLETE  PRACTICAL  MACHINIST. 


and  is  constructed  as  shown  in  Fig.  110.  The  plate  F 
has  four  slots  as  A  B,  and  through  these  and  the  face 
plate  pass  bolts  C  D,  on  which  are  small  sliding  blocks 
fitting  into  the  slots  in  F.  The  work  driving  pins 
P  P  arc  threaded  into  nuts  that  are  iw  T  grooves,  pro- 

Fig.  110. 


vided  in  F.  When  the  pins  meet  the  work  driver  the  plate 
F  moves  upon  the  face  plate,  giving  both  pins  an  equal 
degree  of  driving  pressure. 

When  the  work  requires  to  be  driven  backwards  as 
well  as  forward,  as  in  the  case  of  screw-cutting,  the  dog 
may  be  secured  by  a  set  screw,  such  as  E  in  Fig.  111. 

Fig.  111. 


LATHE  DOGS,   CARRIERS   OR  DRIVERS.        119 


For  taper  threads,  however,  the  set  screw  must  allow 
the  dog  end  to  move  in  the  slot. 

For  driving  bolts  the  driver  may  be  formed  as  in  Fig. 
112  and  bolted  to  the  face  plate,  which  saves  the  trouble 

Fig.  112. 


Fig.  113. 


of  fastening  the  driver  to  each  bolt.  Fig.  113,  which  1*3 
taken  from  "jThe  American  Machinist," 
represents  an  adjustable  driver  of 
this  kind.  One  of  the  jaws,  it  will  be 
observed,  fits  into  a  dove-tailed  slide- 
way,  and  a  screw  is  provided  whereby 
the  width  of  opening  between  the  jaws 
may  be  adjusted  to  suit  the  size  of  the 
work.  Drivers  of  this  kind  are  es- 
pecially suitable  for  small  work,  as 
they  project  less  and  are  therefore  less 
in  the  way  than  ordinary  drivers,  and 
may  also  be  made  thinner  so  as  to 
accommodate  thin  bolt  heads. 

Fig.  114  represents  tlie  wood  turner's 
spur  centre,  the  wings    being  straight 


120 


COMPLETE  PRACTICAL  MACHINIST. 


on  the  outside  and  coned  within,  so  as  to  compress  the 
wood  around  the  central  point  and  thus  keep  it  true 
while  at  the  same  time  obviating  the  liability  to  split  the 
work. 

Fig.  114. 

A 


For  short  work  the  wood  worker  uses  the  screw  chuck 
shown  in  Fig.  115,  the  work  being  centred  and  driven 
by  the  conical  screw.  For  work  that  is  true,  the  face  A 

Fig.  115. 


A  may  be  made  hollow  as  shown,  which  tends  to  true  the 
work.  Mandrils  or  arbors,  as  the  smaller  sizes  are  usually 
termed,  should  have  their  centres  formed  as  in  Fig.  116, 
the  countersink  being  double,  or  else  there  should  be  a 
flat  recess  turned  about  the  countersink,  the  object  being 


LATHE  A  R 110  US. 


121 


in  botli  cases  to  prevent  the  blows  given  to  drive  the  man- 
dril into  the  work  from  bruising  the  centres  and  causing 
them  to  run  out  of  true.  Mandrils  should  be  made 


Fig.  116. 


slightly  taper,  and  made  of  wrought-irou,  or  what  is  better, 
hardened  steel. 

Fig.  117  represents  an  adjustable  arbor   or   mandril. 


Fig.  117. 


Fig.  118. 


The  body  A  is  coned 
and  the  sleeve  is  split,  as 
JB  shown  in  Fig.  118,  so  that 
by  means  of  the  nut  the 
sleeve  may  be  forced  up  the 
arbor  and  its  diameter  made 
to  unscrew  to  fit  the  bore  of 
the  work.  Expanding  man- 


122  COMPLETE  PRACTICAL  MACHINIST. 

drils  are  especially  useful  for  holes  that  are  reamed, 
because  as  the  reamer  wears,  the  size  of  hole  it  produces 
diminishes  and  will  not  fit  a  solid  standard  parallel 
arbor. 

Fig.  119  represents  a  threaded  arbor  for  work  that  is 
tapped,  and  it  is  seen  that  if  the  hole  is  not  tapped  quite 
true  with  the  face  the  work  will  cant  over  and  the  facing 

Fig.  119.  Fig.  120. 

c 

M  T 


will  not  be  true  with  the  thread  axis.  This  may  he 
avoided  by  using  the  arbor  shown  in  Fig.  120,  a  ring 
being  interposed  between  the  work  and  the  arbor  shoulder. 
This  ring  has  two  diametrically  opposite  projections,  A  on 
one  side  and  two  B  on  the  other,  which  balances  the  work 
and  permits  it  to  become  locked  true  with  the  thread. 

CENTRING    LATHE   WORK. 

The  centres  of  a  lathe  should  both  be  of  the  same 
degree  of  cone  so  that  the  work  will  not  wear  to  different 

o 

shapes  when  turned  end  for  end  in  the  lathe. 

The  live  centre  should  be  tempered  to  a  blue,  which 
will  preserve  it,  while  leaving  it  quite  soft  enough  to 
enable  it  to  be  turned  up  to  true  it  with  a  fully  hardened 
cutting  tool.  If  a  centre  grinding  device  is  at  hand  the 
centre  may  also  be  hardened  to  a  straw  color.  Fig.  121 
represents  a  centre  grinding  device  for  attachment  to  the 
lathe  slide-rest  in  connection  with  the  tool  post.  It  con- 
sists simply  of  a  countershaft  above,  driven  from  a  pulley 
on  the  lathe  live  spindle. 


LATHE  CENTRE  GRINDING.  123 

The  countershaft  drives  an  emery  wheel  spindle  below, 
which  has  end  motion  through  its  bearings,  so  that  it  may 
be  fed  to  and  fro  along  the  cone  of  the  lathe  centre.  The 


Fig.  121. 


emery  wheel  spindle  is  set  at  such  an  angle  that  the 
wheel  operates  a  rear  side  of  the  lathe  centre,  so  that  the 
wheel  and  the  centre  revolve  in  opposite  directions. 

The  quickest  method   of  centring    lathe   work    is    by 


124 


COMPLETE  PRACTICAL  MACHINIST. 


means  of  a  centring  machine,  such  as  in  Fig.  122,  which 
consists  of  a  live  spindle  to  drive  the  drill,  and  counter- 
shaft and  a  universal  chuck  to  hold  the  work  which  should 
be  freely  supplied  with  oil  during  the  drilling  process. 


Fig.  123  represents  a  centre-drilling  attachment  for 
)athe  work.  In  the  tail  spindle  T  is  a  cup  or  coned  chuck 
D  to  hold  that  end  of  the  work  W  true.  S  is  a  standard 
bolted  to  the  lathe  shears  and  carrying  two  fixed  pins  P 


CENTRING  LATHE   WORK. 


125 


which  are  each  enveloped  by  a  spiral  spring.  G  is  a  piece 
having  arms  fitting  over  the  pins  P,  and  is  capped  or 
covered  to  receive  the  other  end  of  the  work.  A  small 
hole  through  the  centre  of  G  admits  the  drill.  It  is  ob- 
vious that  when  the  tail  spindle  T  is  fed  up,  it  will  feed 
the  work  to  the  drill,  the  piece  G  moving  with  the  work 
against  the  pressure  of  the  springs  or  pins  P. 

Fig.  123, 


Fig.  124  represents  a  combined  drill  and  countersink 
for  centre  drilling,  the  drill  and  countersink  being  in  one 
piece.  Fig.  125  represents  a  combined  drill  and  counter- 

Fig.  124. 


sink,  in  which  a  small  twist-drill  is  let  into  the  counter- 
sink and  secured  by  a  small  set  screw  S  so  that  the  drill 
may  be  moved  outward  as  it  wears  shorter.  When  very 
true  work  is  required  it  is  preferable  to  so  shape  the 
countersink  that  the  lathe  centre  will  first  bear  at  the 
smallest  part  of  the  cone  as  is  shown  in  Fig.  126.  This 
will  cause  the  countersink  to  wear  and  keep  true  with  the 
hole. 

If  the  centre  drilling  is  to  be  done  by  hand  it  is  very 


126 


COMPLETE  PRACTICAL  MACHINIST. 


important  to  relax  every  few  seconds  the  hold  upon  the 
work  sufficiently  to  permit  it  to  make  about  a  third  of  a 


Fig.  126. 


Fig.  127. 


revolution,  which  may  be 
done  while  the  other  hand 
is  supplying  oil  to  the 
drill.  The  object  and 
effect  of  this  is  to  cause 
the  centre  drilling  to  be 
true,  which  otherwise  it 
would  not  be,  especially 
if  the  work  is  compara- 
tively heavy,  or  heavier 
on  one  side  than  on  an- 
other. 

If,  however,  the  work 
requires  to  run  very  true, 
as  in  the  case  of  recen- 

triug  work  which  has  once  been  turned,  the  square  centre 
must  be  employed  to  cut  the  centre  of  the  worl^  true  to 
the  circumference.  A  square  centre  is  a  centre  fitted  to 
the  lathe  in  the  same  manner  as  the  common  centre,  but 
having  four  flat  sides  ground  upon  its  conical  point,  all 
four  sides  meeting  at  the  point,  and  having  sharp  edges 
as  shown  in  Fig.  127,  the  flutes  serving  to  reduce  the 
area  of  surface  to  be  ground  up  when  sharpening  the  cut- 
ting edges. 

To  recentre  work  that  has  already  been  turned,  the 
square  centre  is  put  in  the  tailstock  spindle  of  the  lathe, 
in  the  same  way  as  the  ordinary  centre  is  placed,  the 
work  having  a  dog  or  driver  placed  on  it,  as  if  the  inten- 
tion were  to  take  a  cut  with  the  work  placed  in  the 
lathe  between  the  centres.  A  piece  of  iron  or  steel,  hav- 
ing a  hollow  or  flat  end  (as,  for  instance,  the  butt  end  of 
ti  tool)  must  then  be  fastened  in  the  tool  post  of  the  lathe  ; 
then  the  lathe  may  be  started  and  the  tool  end  wound 
against  the  end  of  the  work  (close  to  the  square  centre) 


CENTRING  LATHE   WORK.  127 

until  it  touches  it  and  forces  it  to  run  truly,  in  which 
position  the  tool  end  is  left,  while  the  square  centre  is  fed 
up  and  into  the  work  until  the  latter  is  true,  when  the 
operation  will  be  completed.  Before  any  turning  is  done 
to  the  diameter  of  any  lathe  work  which  runs  between  the 
centres,  the  ends  of  such  work  should  be  made  true; 
because  if  there  be  a  projecting  part  on  the  end,  or  if  the 
latter  is  not  quite  true,  the  centre  gradually  moves  over 
to  the  lowest  side,  as  shown  in  Fig.  128,  it  being  obvious 
that  the  countersink  would  move  over  as  it  wore  from  the 
side  C  towards  the  side  D  of  the  work. 

All  work  which  requires  to  be  turned  at  both  ends  (and 
hence  must  be  turned  or  placed  end  for  end  in  the  lathe) 
should   be  roughed  out  (that 
is,  cut  down  to  nearly  the  re-  ^19-  128. 

quired  size)  all  over  before 
any  part  of  it  is  finished,  or, 
when  turned  end  for  end  in 
the  lathe,  the  part  first  turned 
up  will  run  out  of  true  with 
the  part  last  turned  up,  though 
the  lathe  centres  may  be  correctly  placed.  This  may  be 
caused  by  the  centres  of  the  work  moving  a  little  as  they 
come  to  their  bearings  on  the  lathe  centres,  or  in  conse- 
quence of  breaking  the  skin  of  the  work  ;  for  nearly  all 
work  alters  in  form  as  its  outside  skin  is  removed,  especi- 
ally work  in  cast-iron. 

FINISHING    LATHE    WORK. 

The  process  to  be  adopted  in  finishing  lathe  work  de- 
pends upon  the  degree  of  polish  it  is  required  to  have. 

Small  work  may  be  given  the  highest  degree  of  polish 
by  the  use  of  the  file  and  emery  paper.  The  finishing  cut 
should  be  taken  with  a  sharp  tool  and  as  smoothly  as 
possible,  so  as  to  have  as  little  work  as  posssible  for  the 
file  to  do,  because  much  filing  will  make  the  work  out  of 


128  COMPLETE  PRACTICAL  MACHINIST. 

round.  Nothing  coarser  than  a  dead  smooth  file  should 
be  used,  the  work  being  run  at  a  quick  speed,  or  say  at  a 
circumferential  speed  of  not  less  than  about  170  feet  per 
minute. 

The  file  should  be  applied  lightly  to  the  work  and  with 
quick  strokes,  for  if  the  file  is  held  stationary,  the  filings 
will  become  locked  in  the  file  teeth,  forming  pins,  which 
will  cut  scratches. 

To  prevent  this  we  may  apply  either  chalk  or  oil  to  the 
file  and  clean  it  a  for  one  dozen  strokes  or  so,  so  as  not  to 
permit  it  to  clog.  When  chalk  is  use.!,  simply  brushing 
the  hand  over  the  file  \\ill  suffice. 

EMERY    CLOTH    AND    PAPER. 

For  ordinary  work  the  common  grades  of  emery  paper 
and  cloth  may  be  employed,  the  finest  being  flour  emery 
cloth  or  paper.  The  same  grade  of  emery  will  cut  coarser 
if  placed  on  cloth  than  if  on  paper,  because  the  surface 
of  the  cloth  is  not  so  smooth  and  even  as  that  of  the  paper, 
and  the  consequence  is  that  the  grains  of  emery  which  are 
attached  to  the  high  spots  on  the  cloth  present  a  keener 
cutting  edge  and  surface  to  the  work  than  the  rest  of  the 
surface.  The  main  advantage  of  emery  cloth  lies  in  that 
it  will  wear  longer  because  it  is  not  so  apt  to  tear.  To 
fit  emery  cloth  or  paper  for  very  fine  work  it  should  be 
used  upon  the  work  until  the  entire  surface  becomes  worn 
even  and  glazed ;  the  more  it  is  worn  and  glazed  the  finer 
it  will  finish,  and  this  remark  applies  equally  to  all  kinds 
of  emery  cloth  and  paper,  or  crocus  cloth.  There  is,  how- 
ever, an  emery  paper  much  finer  than  any  other,  its  grades 
ranging  from  1  to  0000,  and  it  will  produce  a  finish  so  fine 
as  to  give  the  work  a  finish  and  appearance  equal  to  the 
finest  silver  or  nickel-plating. 

The  method  of  using  to  produce  a  really  fine  finish  is  to 
revolve  the  work  very  fast  ill  the  lathe  and  to  keep  the 


EMERY  POLISHING. 


129 


emery  paper  moving  rapidly,  endwise  of  the  work,  so  that 
the  marks  shall  cross  each  other  at  a  very  obtuse  angle. 
The  coarser  grades  of  cloth  should  be  applied  first,  each 
successive  grade  being  used  until  it  has  entirely  removed 
the  marks  left  by  the  grade  previously  used.  The  final 
polish  is  given  by  number  0000  paper,  moved  laterally 

Fig.  129 


Fig.  130. 


along  the  work  very  slowly,  and  under  a  very  light  pres- 
sure. To  prepare  the  paper  for  the  final  finishing  we 
must  take  the  0000  paper,  and,  giving  the  work  a  coating 
of  oil  barely  sufficient  to  dull  the  polish,  apply  the  paper, 
continually  reversing  its  position  in  the  hand  so  that  all 
parts  will  become  worn,  the  effects  of  the  slight  oiling 
being  to  cause  the  particles  of  metal  cut  off  the  work  to 


130 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  131. 


adhere  to  and  form  a  glaze  upon  the  surface  of  the  emery 
paper,  and  all  metals  polish  best  by  being  rubbed  with  a 
glazed  surface  composed  of  minute  particles  of  the  same 
metal  as  themselves  ;  it  follows,  then,  that  the  more  emery 
paper  or  cloth  becomes  worn  the  finer  it  will  polish. 

For  larger  and  rougher  work 
the  filing  may  be  done  by  an 
ordinary  smooth  file  and  suc- 
ceeded by  a  polishing  clamp 
consisting  of  two  pieces  of  soft 
-wood  hinged  by  leather  and 
containing  holes  to  receive  dif- 
ferent sizes  of  work.  The  work 
is  supplied  with  grain  emery 
and  oil,  and  is  run  at  a  quick 
speed,  the  clamp  being  closed 
firmly  upon  it  and  gradually 
moved  to  and  fro.  Towards 
the  last  of  the  process  no  fresh 
emery  is  applied,  which  makes 
the  polish  more  perfect. 

Grinding  clamps  for  finish- 
ing work  to  gauge  diameters 
are  made  as  in  Fig.  129,  the 
two  hinged  halves  being  made 
of  cast-iron  recessed  so  as  to 
receive  a  lining  of  babbitt 
metal,  and  held  together  by  a 
screw  D  and  pin  A.  In  the 
small  sizes  a  split  bush,  such  as 
in  Fig.  130,  will  serve. 
For  grinding  out  bores  an  arbor,  A  A,  Fig.  131,  is  em- 
ployed, having  in  it  a  groove  C.  B  is  a  babbitt  metal 
bush  cast  on  its  projection  into  the  groove  C  serving  as  a 
driving  key.  As  the  diameter  of  B  decreases,  it  may  be 
driven  further  up  the  arbor  or  mandril,  which,  being  taper, 
will  expand  with  B. 


TWO  JAWED  LATHE  CHUCKS. 


131 


132. 


LATUE   CHUCKS. 

Lathe  chucks  may   be  divided   into  three  classes,  as 
follows  : 

1st.  Those  in  which  the  jaws  are  actuated  simultaneous- 
ly, winch  are  called  universal  chucks. 

2d.  Those  in  which  the  jaws  are  actuated  separately, 
which  are  called  independent  chucks,  and 

3d.  Those  in  which  the 
mechanism  is  so  devised 
that  the  jaws  may  be  oper- 
ated either  separately  or 
independently  at  will, 
which  are  termed  com  hi 
nation  chucks. 

Figs.  132  and  133  repre- 
sent the  Horton  two-jawed 
chuck,  with  false  or  slip 
faces  which  are  removable, 
so  that  jaws,  having  grip- 
ping surfaces  of  various 
Chapes  to  suit  the  shape 
of  the  work,  may  be  em- 
ployed. The  slips  are  dove- 
tailed into  the  jaws  and 
further  secured  by  pins. 

Fig.  134  represents  what 
is  called  a  box-body  chuck, 
which  is  used  to  hold  the 
brass  turner's  work.  In 

some  of  these  chucks  the  jaws  are  operated  simultaneously 
by  a  right  and  left-hand  screw,  while  in  others,  each  jaw 
has  its  own  separate  screw. 

In  the  larger  sizes  of  chucks,  there  are  usually  either  three 
or  four  jaws.  In  a  three-jawed  chuck  the  work  will  be  held 
with  equal  pressure  by  each  jaw,  because  the  fulcrum  of 


Fig.  133. 


132 


COMPLETE  PRACTICAL  MACHINIST. 


the  bite  of  each  jaw  is  taken  off  the  other  two  jaws,  while 
in  a  four-jawed  chuck,  two  opposite  jaws  may  take  all  the 
strain,  leaving  the  other  two  free  from  contact  with  the 
work.  It  is  obvious,  therefore,  that  for  rough  work,  or  work 

Fig.  134. 


that  is  not  cylindrical,  three  jaws  are  preferable  to  four, 
but  if  the  work  is  true,  then  the  four  jaws  are  preferable, 
inasmuch  as  they  hold  the  work  at  four  points  instead  of 
at  three. 


CHUCKS. 


133 


Fig.  135  represents  the  Sweetland  Chuck,  which  may 
be  used  as  an  independent  or  as  a  universal  chuck.  Each 
of  the  screws  lor  operating  the  jaws  is  provided  with  11 
bevel  pinion,  and  behind  these  pinions  is  a  ring  provided 
with  teeth,  and  which  may  be  caused  to  engage  with  or 
disengage  from  the  pinions  as  follows:  The  width  of  the 
rack  has  a  beveled  step,  the  outer  being  thicker  than  the 
inner  diameter.  Between  this  ring  or  rack  and  the  face 
of  the  chuck  is  placed,  beneath  each  jaw,  a  cam  block 

Fig.  135. 


beveled  to  correspond  with  the  beveled  edge  of  the  ring 
step. 

Each  cam  block  stem  passes  through  radial  slots  in  the 
face  of  the  chuck,  so  that  it  may  be  moved  towards  or 
away  from  the  centre  of  the  chuck.  When  it  is  moved  in, 
its  cam-head  passes  into  the  recess  or  thin  part  of  the  ring- 
rack  which  then  falls  back  out  of  gear  with  the  jaw-screw 
pinion.  But  when  it  is  moved  outward  the  cam-head  slides 
12 


134 


COMPLETE  PRACTICAL  MACHINIST. 


(on  account  of  the  beveled  edge)  under  the  ring-rack  and 
places  it  in  gear  with  the  jaw-screw  pinion.  Thus  to  change 
the  chuck  from  an  independent  one  to  a  universal  one  all 
that  is  necessary  is  to  push  outwards  the  bolt-head  of  the 
cam-block  stems,  said  heads  being  outside  the  chuck.  The 
washers  beneath  these  heads  are  dished  to  give  them  elas- 
ticity and  enable  them  to  steady  the  cams  without  undue 
friction. 

To  enable  the  jaws  to  be  set  true  for  using  the  chuck  as 
a  universal  one,  a  circle  is  marked  on  the  chuck  face,  and 
to  this  circle  the  edges  of  all  the  jaws  must  be  set  before 
operating  the  cams  to  put  the  rack  ring  in  gear. 

Fig.  136. 


Fig.  136,  represents  a  new  drill  chuck  by  the  Russell 
Tool  Co.,  of  Boston,  Mass.,  the  object  of  which  is  to  pre- 
vent the  slipping  common  to  small  chucks.  The  jaws  A 
are  placed  in  the  line  of  strain  so  as  to  drive  rather  than 
pull  the  work,  and  are  serrated  to  increase  the  grip. 
The  piece  B  moves  out  with  the  jaws  to  support  them,  and 
the  jaws  are  provided  with  lugs  E,  which  afford  them  ex- 
tra support.  As  a  result  of  these  features,  the  chuck  will 
hold  sufficiently  firmly  to  permit  of  its  being  used  to  drive 
work  (having  a  diameter  equal  to  the  full  capacity  of 
the  chuck)  to  be  turned  with  the  lathe  tools. 


CHUCKS.  135 

Chuck  dogs  are  detached  dogs  which  fit  into  the  square 
holes  of  the  chuck  plate  or  face  plate,  being  held  to  the 
plate  by  a  nut  and  washer.  These  dogs  are  movable  to 
any  part  of  the  plate,  their  position  being  regulated  to 
conform  to  the  shape  of  the  work,  which  renders  possible 
their  employment  in  cases  where  a  dog  chuck  would  be 
of  no  service ;  such,  for  instance,  as  holding  a  triangular 
or  irregular  shaped  piece  of  work.  The  centre  line  of 
the  screw  should  stand  exactly  parallel  to  the  face  of 
the  face  plate,  or  tightening  the  screws,  which  in  this  case 
grip  the  work,  will  force  the  latter  towards  or  away  from 
the  face  of  the  plate,  according  to  the  direction  in  which 
the  screws  are  out  of  true.  The  screws  should  have  their 
ends  turned  down  below  the  thread,  and  should  be  hard- 
ened as  directed  for  bell  chuck  screws,  since  these  screws 
may  be  also  reversed  in  the  dog  for  some  kinds  of  work. 
The  dog  should  be  screwed  very  firmly  against  the  face 
plate,  so  as  to  avoid  their  springing. 

Universal  or  scroll  chucks,  containing  screws  or  gear 
wheels  which  are  enclosed,  should  be  occasionally  very 
freely  supplied  with  oil,  and  the  chuck  worked  so  as  to 
move  the  jaws  back  and  forth  to  the  extreme  end  of  their 
movement,  so  as  to  wash  out  any  particles  of  metal  or 
dust  which  may  have  lodged  or  collected  in  them  ;  for 
proper  cleaning  will  reduce  the  natural  wear  to  a  min- 
imum, and  prevent  the  internal  parts  from  cutting,  as 
they  are  otherwise  apt  to  do. 

When  the  work  is  liable  to  spring,  from  the  pressure  of 
the  jaws  of  a  chuck,  those  jaws  may  be  slacked  back  a 
little  previous  to  taking  the  finishing  cut,  during  whicn 
the  work  ne^d  not  be  held  so  tightly. 

From  what  has  been  already  said  it  will  be  obvious  that 
it  is  of  great  importance  that,  in  addition  to  the  jaws  of  a 
chuck  being  well  fitted  to  the  plate,  there  should  be  a 
large  amount  of  wearing  surface,  so  as  to  prevent  as  far  as 
possible  the  jaws  wearing  loose  in  their  slides. 


CHAPTER    VI. 

TURNING   ECCENTRICS. 

IF  an  eccentric  has  a  hub  or  boss  on  one  side  only  of  its 
bore  (as  in  the  case  of  those  for  engines  having  link 
motions,  where  it  is  desirable  to  keep  the  eccen cries  as  close 
together  as  possible  in  order  to  avoid  offset  either  in  the 
bodies  or  double  eyes  of  the  eccentric  rods),  the  first  opera- 
tion to  be  performed  in  turning  it  up  is  to  chuck  it  with 
the  hub  side  towards  the  face  plate  of  the  lathe,  setting  it 
true  with  its  outside  diameter  (irrespective  of  the  hole  and 
hub  running  out  of  true),  and  to  then  face  up  the  outside 
face.  It  must  next  be  chucked  so  that  the  face  already 
turned  will  be  clamped  against  the  face  plate,  setting  the 
eccentric  true  to  bore  the  hole  out,  and  clamping  balance 
weights  on  the  face  plate,  opposite  to  the  overhanging 
part  of  the  eccentric.  The  hole,  the  face  of  the  hub,  the 
hub  itself  (if  it  is  circular),  and  the  face  of  the  eccentric 
must  be  roughed  out  before  any  of  them  are  finished, 
when  the  whole  of  them  may  be  finished,  to  the  requisite 
sizes  and  thicknesses.  The  eccentric  must  then  be  turned 
about  and  held  to  the  chuck-plate  by  a  plate  or  plates 
clamping  the  hub  or  boss  only,  the  diameter  of  the  eccen- 
tric being  set  true  to  the  lines  marked  to  set  it  by ;  then 
the  diameter  of  the  eccentric  may  be  turned  to  fit  the  strap, 
the  latter  having  been  taken  apart  for  that  purpose.  The 
reason  for  turning  the  strap  before  the  eccentric  is  turned 
is  (as  may  be  inferred  by  the  above)  that  the  strap  can 
be  fitted  to  the  eccentric  while  the  latter  is  in  the  lathe, 
whereas  the  eccentric  cannot  be  got  into  the  strap  while 
136 


TURNING   ECCENTRICS.  137 

the  strap  is  in  the  lathe.  By  this  method,  the  outside  of 
the  eccentric  will  be  turned  true  with  a  face  that  lias  been 
turned  at  the  same  chucking  at  which  the  hole  was 
bored ;  while  the  eccentric  will  stand  sufficiently  far  from 
the  chuck  to  permit  of  the  strap  being  tried  on  when  it  is 
necessary.  And,  moreover,  the  skin  of  the  metal  will  have 
been  removed  on  three  out  of  the  four  faces  before  either 
of  the  working  parts  (the  bore  and  the  outside  diameter) 
is  finished;  and  as  a  consequence,  the  work  will  remain 
true,  and  not  warp  in  consaquence  of  the  removal  of  the 
skin.  Furthermore,  upon  the  truth  of  the  last  chucking 
only  will  the  truth  of  the  whole  job  depend  ;  and  if  the 
face  plate  of  the  lathe  is  a  trifle  out  of  true,  the  eccentric 
will  only  be  out  to  an  equal  amount.  It  is  not  an  un- 
common practice  (but  a  very  reprehensible  one). to  face  off 
the  plain  side  of  the  eccentric,  and  to  then  bore  the  hole 
and  turn  the  outside  diameter,  with  the  plain  face  clamped 
in  both  cases  to  the  face  plate.  The  fallacy  of  this  method 
lies  in  the  fact  that,  by  such  a  procedure,  the  eccentric  will 
be,  when  finished,  out  of  true  to  twice  the  amount  that  the 
face  plate  is  out  of  true. 

The  strap  should  have  a  piece  of  thin  sheet  tin  placed 
between  the  joint  of  the  two  halves  before  it  is  turned  out, 
which  tin  should  be  taken  out  when  the  turning  is  com- 
pleted, and  the  strap  bolted  together  again.  The  size  for 
the  eccentric  will  then  be  from  crown  to  crown  of  each 
half  of  the  strap. 

The  object  of  inserting  the  tin  is  to  make  each  half  of 
the  eccentric  bed  well  upon  the  crown,  and  to  prevent  it 
from  bearing  too  hard  upon  the  points,  as  all  straps  do  if 
the  joint  is  not  kept  a  little  apart  during  the  boring  pro- 
cess. If  the  eccentric  is  already  turned,  an  allowance  may 
be  made  for  the  thickness  of  the  sheet  tin  between  the 
strap  joint  by  placing  a  piece  of  the  same  tin  beneath  one 
of  the  caliper  points  when  gauging  the  eccentric  to  take  the 
size  for  the  strap. 
12 


138  COMPLETE  PRACTICAL  MACHINIST. 

Eccentrics  having  a  proportionally  large  amount  of 
throw  upon  them  are  sometimes  difficult  to  hold  firmly, 
while  their  outside  diameters  are  being  turned  to  fit  the 
strap,  because  the  hub  which  is  bolted  against  the  face 
plate  is  so  far  from  the  centre  of  the  work  that,  when  the 
tool  is  cutting  on  the  side  of  the  eccentric  opposite  to  the 
hub,  the  force  of  the  cut  is  at  a  considerable  leverage  to 
the  plates  clamping  the  eccentrics  ;  and  the  latter  are,  in 
consequence,  very  apt  to  move  if  a  heavy  cut  is  taken  by 
the  tool.  Such  an  eccentric,  however,  usually  has  open 
spaces  in  its  throw,  which  spaces  are  placed  there  to 
lighten  it;  the  method  of  chucking  may,  under  such  cir- 
cumstances, be  varied  as  follows :  The  outside  diameter  of 
the  eccentric  may  be  gripped  by  the  dog  chuck,  if  the  dogs 
of  the  chuck  project  far  enough  out  to  reach  it  (otherwise 
the  dogs  may  grip  the  hub  of  the  eccentric),  while  the  hole 
is  bored  and  the  plain  face  of  the  eccentric  turned.  The 
eccentric  must  then  be  reversed  in  the  lathe,  and  the  hub 
and  the  face  on  that  side  must  be  turned.  Then  the  plain 
face  of  the  eccentric  must  be  bolted  to  the  face  plate  by 
plates  placed  across  the  spaces  which  are  made  to  lighten 
the  eccentric,  and  by  a  plate  across  the  face  of  the  hub. 
The  eccentric  being  set  true  to  the  lines  may  then  be 
turned  on  its  outside  diameter  to  fit  the  strap ;  to  facilitate 
which  fitting,  thin  parallel  s  rips  may  be  placed  between 
the  face  plate  and  the  plain  face  of  the  eccentric  at  this 
last  chucking.  It  will  be  observed  that,  in  either,  method 
of  chucking,  the  outside  diameter  of  the  eccentric  (that  is 
to  say,  the  part  on  which  the  strap  fits)  is  turned  with  the 
face  which  was  turned  at  the  same  chucking  at  which  the 
hole  was  bored,  clamped  to  the  face  plate.  In  cases  where 
a  number  of  eccentrics  having  the  same  size  of  bore  and 
the  same  amount  of  throw  are  turned,  there  may  be  fitted 
to  the  face  plate  of  the  lathe  a  disk  of  sufficient  diameter 
to  fit  the  hole  of  the  eccentric,  said  disk  being  fastened  to 
the  face  plate  at  the  required  distance  from  the  centre  of 


TURNING  ECCENTRICS.  153 

the  lathe  to  give  the  necessary  amount  of  throw  to  the 
eccentric.  The  best  method  of  fastening  such  a  disk  to  the 
face  plate  is  to  provide  it  with  a  plain  pin  turned  true  with 
the  disk,  and  let  iL  fit  a  hole  (bored  in  the  face  plate  to 
receive  it)  sufficiently  tightly  to  be  just  able  to  be  taken 
in  and  out  by  the  baud,  the  pin  being  provided  with  a  screw 
at  the  end  so  that  it  can  be  screwed  tight,  by  a  nut,  to  the 

Fig.  137. 


Fig.  138. 


face  plate.  The  last  chucking  of  the  eccentric  is  then  per- 
formed by  placing  the  hole  of  the  eccentric  on  the  disk, 
which  will  insure  the  correctness  of  the  throw  without  the 
aid  of  any  lines  on  the  eccentric  which  may  be  set  as  true 
as  the  diameter  of  the  casting  will  permit,  and  then  turned 
to  fit  the  strap.  A  similar  disk,  used  in  the  same  manner, 
may  be  employed  on  cranks,  to  insure  exactness  in  their 
throw. 


140  COMPLETE  PRACTICAL  MACHINIST. 

TURNING    CRANKS. 

A  crauk  having  a  plain  surface  on  its  back  should  have 
such  surface  planed  true.     The  large  hole  should  be  bored 

Fig.  139. 


first,  the  crank  being  clamped  with  its  planed  surface  to 
the  chuck  plate  of  the  lathe,  when  the  hole  mny  be  bored 


CHUCKING  CROSSHEADS. 


141 


and  the  face  of  the  hub  trued  up.  To  bore  the  hole  for 
the  crank  pin,  clamp  the  face  of  the  hub  of  the  crank, 
which  has  been  trued  up,  against  the  plate  of  the  lathe 
(the  crank  pin  end  of  the  crank  being  as  it  were  sus- 
pended) ;  then  bolt  two  plates  to  the  chuck  plate,  one  on 
each  side  of  the  crank  at  the  end  to  be  bored,  and  place 
th'jm  so  that  their  ends  just  come  in  contact  with  the 
crank  end. 

TO    CHUCK    A   CROSSHEAD. 

The  bores  of  a  crosshead  must  be  at  a  right  angle  with 
the  axes  intersecting,  and  to  accomplish  this  great  care  is 
necessary  in  marking  the  lines  that  are  to  be  used  in 


Fig.  140. 


Fig.  141. 


chucking  it  in  the  lathe.  When  the  forging  is  true  enough, 
it  is  the  best  plan  to  let  the  crosshead  cheeks  rest  upon 
the  marking-off  table  or  plate,  without  any  paper  or  other 


142  COMPLETE  PRACTICAL  MACHINIST. 

packing  beneath  them,  as  shown  in  Fig.  137,  so  that  th6 
square  may  be  set  against  these  two  edges  in  the  subse- 
quent chuckings.  If  the  edges  are  out  of  true,  so  that 
the  work  will  not  be  true  if  marked  out  by  them,  they 

Fig.  142. 


should  be  made  true.  This  being  done,  the  crosshend 
should  be  laid  upon  a  plate,  as  in  Fig  138,  and  the  centre 
line  A  A  marked  around  it.  The  centre  line  B  B  is  next 
to  be  marked  at  a  right  angle  to  A  A,  and  to  do  this  the 


CHUCKING  CROSSHEADS. 


143 


Fig.  143. 


crosshead  should  be  turned  over  oil  the  table,  as  ill  Fig. 
137,  and  squared  by  the  edges  C  C  of  the  cheeks,  the  line 
A  A  standing  vertical.  When  B  B  is  drawn,  we  may 
mark  off  the  holes  from  the  intersection  of  A  A  with  B 
B,  and  the  thickness  of  the  cheeks  from  line  B  B,  and  the 
crosshead  is  ready  to  chuck. 

The  first  chucking  should  be  as  in  Fig.  139,  one  cheek 
being  laid  upon  and  bolted  to  an  angle  plate,  the  cross- 
head  being  set  to  the  dotted  circle 
on  the  end  face  of  the  hub  and 
tested  with  a  square  applied  to 
the  dotted  line  F  in  Fig.  140,  and 
also  to  the  centre  line  A  in  Fig. 
141,  so  that  the  crosshead  may  be 
set  square,  as  well  as  having  the 
circle  run  true.  At  this  chucking 
the  hole  for  the  piston-rod  would 
be  bored,  and  the  hub  would  be 
faced  and  turned.  The  second 
chu<  king  would  be  as  in  Fig.  142, 
the  faced  end  of  the  hub  being 
bolted  to  the  angle  plate,  and  a 
square  being  applied  to  the  edges 
C  C,  as  in  Fig.  143,  while  the 
dotted  face  of  the  circle  on  the 
face  of  the  hub  is  set  to  run  true, 
when  the  cheeks  may  be  bored 
and  faced  inside  and  out,  with  the 
assurance  that  the  work  will  be  true  and  the  holes  at  right 
angles  to  one  another. 

COUNTERBALANCING   WORK. 

When  work  is  to  be  counterbalanced,  the  weight  should 
be  such  as  will  effect  the  counterbalance  when  placed  at  a 
distance  from  the  line  of  centres  equal  to  the  distance  from 
that  line  of  the  heaviest  part  to  be  counterbalanced,  and 


144  COMPLETE  PRACTICAL  MACHINIST. 

when  the  counterbalancing  is  to  be  done  on  work  held 
between  the  centres,  for  example  in  the  case  of  crank 
shafts,  it  is  preferable  to  bolt  the  weight  to  the  work  itself 
aud  not  to  the  faceplate  of  the  lathe.  In  the  absence  of 
proper  counterbalancing  the  work  is  apt  to  be  turned 
elliptical. 

BORING    LINKS   OR   LEVERS. 

In  boring  a  number  of  lever  arms  or  other  work  having 
holes  requiring  to  be  of  precisely  the  same  distance  apart, 
we  bore  and  finish  one  with  great  exactitude.  Then  after 
that  one  is  bored,  and  the  faces  of  the  hub  are  faced  off 
true  with  the  hole,  a  pin,  as  shown  in  Fig.  144,  should  be 
made,  the  diameter  of  the  part  A  being  made  to  neatly  fit 
one  of  the  holes  in  the  end  of  the  arms  or  levers,  and 
being  made  longer  in  length  than  is  the  length  of  the 
lever  hole  into  which  it  fits.  B  is  a  washer,  turned  to  fit 
easily  to  the  diameter  of  A,  and  C  is  a  collar,  solid  with 
A.  D  is  a  stem,  turned  parallel  and  true ;  and  it  is  a  little 

Fig.  144. 


less  in  length  than  the  thickness  of  the  chuck  plate  upon 
which  the  arm  is  to  be  held  while  the  holes  are  being 
bored.  Upon  each  end  a  screw  is  provided  to  receive  d 
nut.  The  use  of  this  stud  is  as  follows  :  Upon  the  chuck 
plate  of  the  lathe  or  boring  machine,  and  at  the  requisite 
distance  from  the  centre,  is  bored  a  hole  to  receive  at  a 
close  fit  the  plain  pait  D,  of  the  stud ;  and  into  this  hole 
that  end  of  the  stud  is  fastened  by  means  of  a  nut.  One 


TURNING  LEVERS. 


145 


end  of  the  lever  or  arm  (being  bored  to  fit  the  part  A  of 
the  stud)  is  placed  thereon,  the  stud  being  bolted  to  the 
chuck  plate  while  the  hole  at  the  opposite  end  is  being 
bored :  thus  insuring  that  the  holes  are  exactly  the  same 
distance  apart  in  all  the  levers.  The  manner  of  chucking 
is  shown  in  Fig.  145  in  which  A  represents  a  portion  of 
the  chuck,  B  the  lever  or  arm  to  be  bored,  C  the  stud,  and 
D  D  the  plates  bolted  against  the  chuck  so  that  their  ends 
contact  with  the  stem  of  the  work  to  prevent  it  from 

Fig.  145. 


moving  sideways  during  the  operation  of  boring.  The  use 
of  this  stud,  modified  in  shape  to  suit  the  work,  is  also 
applied  to  the  turning  of  cranks,  eccentrics,  and  other 
similar  work,  requiring  unusual  exactitude  in  the  position 
of  a  hole  or  holes,  or  of  a  diameter  in  its  position  relative 
to  a  hole. 

TURNING   PISTONS   AND   RODS. 

A  piston  should  first  be  bored  to  receive  the  piston  rod. 
The  next  operation  is  to  rough  out  the  body  of  the  piston 
13 


146  COMPLETE  PRACTICAL   MACHINIST. 

rod  and  to  then  fit  it  to  the  piston.  The  piston  is  then 
made  fast  to  the  rod,  by  the  key,  the  nut,  or  by  riveting, 
as  the  case  may  be,  and  the  piston  and  rod  should  then  be 
turned  between  the  centres.  By  this  means,  the  piston  is 
sure  to  be  true  with  the  rod,  which  would  not  be  the  case 
if  the  piston  and  rod  were  turned  separately.  In  turning 
the  piston  follower,  that  is,  the  disk  which  bolts  to  the 
piston  head  to  retain  the  rings  in  their  places,  slack  back 
the  dogs  or  jaws  of  the  chuck  after  the  roughing  out  is 
complete,  taking  the  finishing  cuts  with  the  jaws  clamped 
as  lightly  as  possible  upon  the  work ;  because  when  the 
jaws  of  a  chuck  are  screwed  upon  the  work  with  great 
force,  they  spring  it  out  of  its  natural  shape. 

PISTON   RINGS. 

The  rings  of  metal  from  which  piston  rings  are  turned 
should  have  feet  cast  upon  one  end,  which  feet  must  be 
faced  up  true  by  taking  a  cut  over  them.  The  ring  should 
then  be  chucked  by  bolting  the  faced  feet  against  the 
chuck  plate,  so  that  the  ring  shall  not  be  sprung  in  chuck- 
ing, as  it  would  be  if  it  were  held  upon  its  inside  or  out- 
side diameter  by  the  jaws  of  a  chuck.  The  inside  and 
outside  diameters  of  the  ring  may  then  be  turned  to  their 
required  dimensions,  and  the  end  face  may  be  trued  up, 
when  the  piston  rings  may  be  cut  off  as  follows: 

First  introduce  the  parting  tool,  leaving  the  ring  suf- 
ficiently wide  to  allow  of  a  finishing  cut  after  cutting  the 
ring  nearly  off;  introduce  a  side  tool,  shown  in  Fig.  36, 
and  take  a  light  finishing  cut  off  the  side  of  the  ring,  and 
then  cut  it  off.  The  end  face  of  the  ring  in  the  lathe  may 
then  be  trued  up  by  a  finishing  cut  being  taken  over  it, 
when  the  parting  tool  may  be  introduced  and  the  process 
repeated  for  the  next  ring. 

Piston  rings  are  sometimes  made  thick  on  one  side  and 
thin  on  the  other  side  of  the  diameter,  the  split  of  the  ring 
being  afterwards  cut  at  its  thinnest  part,  so  that,  when  the 


TURNING  PISTON  RINGS.  147 

ring  is  sprung  into  the  cylinder  (which  is  done  to  make 
the  ring  fit  the  cylinder  tight  and  to  cause  it  to  expand 
as  it  wears,  thus  compensating  for  the  wear),  its  spring 
will  be  equal  all  over  and  not  mainly  on  the  part  of 
the  diameter  at  right  angles  to  the  split,  as  it  otherwise 
would  be. 

The  process  of  turning  such  rings  is  to  face  the  feet  of 
the  ring  from  which  they  are  to  be  cut,  and  then  turn  up 
the  outside  diameter  to  its  required  size.  Then  move  the 
ring  on  the  face  plate  sufficiently  to  cause  it  to  revolve 
eccentrically  to  the  amount  of  the  required  difference 
between  the  thickest  and  thinnest  parts  of  the  ring,  when 
the  inside  diameter  should  be  trued  out,  and  the  rings 
cut  off  as  before  directed. 

The  object  of  turning  the  inside  bore  after  and  not 
before  the  outside  diameter  of  the  ring  is  turned,  is  that, 
during  the  process  of  cutting  off  the  individual  piston 
rings,  the  bore  of  the  ring  will  be  true,  so  that  the  parting 
tool  will  not  come  through  the  ring  at  one  side  sooner 
than  at  the  other;  for  if  this  were  the  case,  the  parting  tool, 
from  its  liability  to  spring  and  its  broad  cutting  surface 
(parallel  to  the  diameter  of  its  cut),  would  be  apt  to 
spring  in,  rendering  the  cutting  off  process  very  difficult 
to  perform  ;  because  if  the  piston  ring  is  cut  completely 
through  on  one  side  and  not  on  the  other,  it  will  probably 
bend  and  spring  from  the  pressure  of  the  parting  tool,  and 
in  most  cases  break  off  before  being  cut  through  at  all 
parts  by  the  tool. 

The  inside  diameter  (or  bore)  of  pic  ton  rings  is  fre- 
quently left  rough,  that  is  to  say,  not  turned  out  at  all ; 
but  whenever  this  is  the  case,  the  splitting  of  the  ring  will 
in  all  probability  cause  one  end  of  the  ring  (where  it  is 
split)  to  move  laterally  one  way  and  the  other  end  to 
move  the  opposite  way,  causing  the  vise  hand  a  great  deal 
of  labor  to  file  and  scrape  the  sides  of  the  ring  true  again. 
The  cause  of  this  spring  is  that  there  is  a  tension  on  the 


148  COMPLETE   PRACTICAL   MACHINIST. 

inside  of  the  ring  (where  it  has  not  been  bored),  tending  to 
twist  it,  which  tendency  is  overcome  by  the  strength  of  the 
ring  so  long  as  it  is  solid  ;  but  when  it  is  split,  the  tension 
releases  itself  by  twisting  the  ring  as  stated. 

The  tension  referred  to  is,  in  all  probability,  caused,  to  a 
certain  extent,  by  the  unequal  cooling  of  the  ring  after  it 
is  cast. 

Iron  and  brass  moulders  generally  extract  castings  from 
the  mould  as  soon  as  they  are  cool  enough  to  permit  of 
being  removed,  and  then  sprinkle  the  sand  with  water  to 
cool  and  save  it  as  much  as  possible.  The  consequence  is 
that  the  part  of  the  casting  exposed  to  the  air  cools  more 
rapidly  than  the  part  covered  or  partly  covered  by  the 
sand,  which  creates  a  tension  of  the  skin  or  outside  of  the 
casting.  The  same  effect  is  produced,  and  to  a  greater 
extent,  if  water  is  sprinkled  on  one  part  of  the  casting  and 
not  on  the  other,  or  even  on  one  part  more  than  on 
another. 

It  has  already  been  stated  that  brasses  contract  a  little, 
sideways,  in  the  process  of  boring,  and  that  work  of  cast 
metal  alters  its  form  from  the  skin  of  the  metal  being 
removed ;  this  alteration  of  form,  in  both  cases,  arises  in 
the  case  of  a  piston  ring  from  the  release  of  the  tension. 

It  sometimes  occurs  that  a  piece  of  work  that  is 
finished  true  in  all  its  parts  may  unexpectedly  require 
a  cut  to  be  taken  off  an  unfinished  part  (to  allow  clear- 
ance or  for  other  cause),  and  that  the  removal  of  the 
rough  skin  throws  the  work  out  of  true  in  its  various  parts, 
as,  for  instance :  a  saddle  of  a  lathe  being  scraped  to  fit  the 
lathe  bed,  and  its  slides  finely  scraped  to  a  surface  plate; 
or  the  rest  itself  being  fitted  and  adjusted  to  the  cross  slide 
of  the  saddle.  If,  when  the  nut  and  screw  of  the  cross 
slide  are  placed  in  position,  the  nut  is  discovered  to  bind 
against  the  groove  (of  the  saddle)  along  which  it  moves 
(the  nut  being  too  thin  to  permit  of  any  more  being  taken 
off  it),  there  is  no  alternative  but  to  plane  the  groove  in 


TURNING  PJSTON  RINGS. 


149 


the  saddle  deeper,  which  operation  will  cause  the  saddle  to 
warp,  destroying  its  fit  upon  the  lathe  bed,  and  the  true- 
ness  of  the  V's  of  the  cross  slide,  and  that  to  such  an 
extent  as  to  sometimes  require  them  to  be  refitted. 

The  evil  effects  of  this  tension  may  be  reduced  to  a 
minimum  by  letting  the  casting  cool  in  the  mould,  or  if 
they  are  taken  from  the  mould  while  still  red  hot,  by 
placing  them  in  a  heap  in  some  convenient  part  of  the 
foundry,  and  covering  them  with  sand  kept  in  that  place 

Fig.  146. 


for  the  purpose ;  and  by  roughing  out  all  the  parts  of  the 
work  which  are  to  be  cut  at  one  chucking  before  finishing 
any  one  part. 

Piston  rings  are  turned  larger  than  the  bore  of  the 
cylinder  which  they  are  intended  to  fit,  and,  as  before 
stated,  sprung  into  the  cylinder.  The  amount  to  which 
they  are  turned  larger  depends  upon  the  form  of  split 
intended  to  be  given  to  the  ring;  if  it  be  a  straight  one, 
cut  at  an  angle  to  the  face  of  the  ring,  which  is  the  form 
commonly  employed,  the  diameter  of  the  ring  may  be 
13* 


150  COMPLETE  PRACTICAL  MACHINIST. 

made  in  the  proportion  of  one-quarter  inch  per  foot  larger 
than  the  bore  of  the  cylinder,  sufficient  being  cut  out  of 
the  ring,  on  one  side  of  the  split,  to  permit  the  ring  to 
spring  into  the  diameter  of  the  cylinder,  when  the  ring 
may  be  placed  in  the  cylinder  and  filed  to  fit,  taking  care 
to  keep  the  ring  true  in  the  cylinder  while  revolving  it  to 
mark  it. 

Fig.  146  represents  an  expanding  chuck  for  holding 
piston  rings  or  similar  work.  It  consists  of  an  arbor  or 
mandril  A,  upon  which  is  the  body  B  of  the  chuck,  whose 
hub  is  coned.  C  is  a  disk  bored  to  fit  the  coned  hub 
of  B,  and  having  four  splits,  one  of  which,  Z,  extends  to 
its  circumference.  E  is  a  ring  to  receive  the  pressure  of 
nut  D,  and  it  is  obvious  that  if  the  latter  be  screwed  up 
upon  A,  then  disk  C  will  be  forced  up  the  cone,  and  its 
diameter  will  enlarge  and  grip  the  bore  of  the  ring  or 
work  R.  The  range  of  an  expansion  chuck  of  this  kind 
is  obviously  small,  hence  it  is  suitable  mainly  for  special 
work. 


CHAPTER    VII. 

HAND-TURNING. 

TURNING  work  in  the  lathe  with  a  tool  held  or  guided 
by  hand,  or,  as  it  is  commonly  termed,  hand-turning,  is  ab 
once  one  of  the  most  delicate  and  instructive  branches  of 
the  machinist's  art,  imparting  a  knowledge  of  the  nature 
and  quantity  of  the  resistance  of  metals  to  being  cut,  of 
the  qualifications  of  various  forms  of  cutting  tools,  and  of 
the  changes  made  in  those  qualifications  consequent  upon 
the  relative  position  or  angle  of  the  cutting  edge  of  the  tool 
to  the  work ;  and  this  knowledge  is  to  be  obtained  in  no 
other  way  than  by  the  practice  of  hand-turning. 

It  is  the  work  of  an  instant  only  to  vary  the  relative 
height  and  angle  of  a  hand  tool  to  the  work,  converting 
it  from  a  roughing  to  a  finishing  tool  or  even  to  a  scraper, 
which  operations  are  difficult  and  sometimes  impracticable, 
if  not  impossible,  of  accomplishment  with  a  tool  held  in  a 
slide  rest. 

The  experience  gained  from  the  use  of  slide  rest  tools  is 
imparted  mainly  through  the  medium  of  the  eyesight, 
whereas  in  the  case  of  a  hand  tool  the  sense  of  feeling 
becomes  an  active  agent  in  imparting,  at  one  and  the 
same  time,  a  knowledge  of  the  nature  of  the  work  and  the 
tool;  so  much  so,  indeed,  that  an  excess  in  any  of  the 
requisite  qualifications  of  a  hand  tool  may  be  readily 
perceived  from  the  sense  of  feeling,  irrespective  of  any 
assistance  from  the  eye ;  and  in  this  fact  lies  the  chief 
value  of  the  experience  gained  by  learning  to  turn  by 
hand. 

151 


152  COMPLETE  PRACTICAL  MACHINIST. 

For  instance,  there  is  no  method  known  to  practice 
whereby  to  ascertain  how  much  power  it  requires  to  force 
a  slide  rest  tool  into  its  cut,  or  to  prevent  its  ripping  in; 
so  that  a  wide  variation,  in  the  tendency  of  such  a  tool  to 
perform  its  allotted  duty  easily  and  without  an  unnecessary 
expenditure  of  power,  may  exist  without  becoming  manifest 
to  any  save  the  experienced  workman  ;  whereas  the  amount 
of  power  required  to  keep  the  cutting  edge  of  a  hand  tool 
to  its  work,  to  hold  it  steadily,  or  to  prevent  it  from  ripping, 
is  communicated  instantly  to  the  understanding  through 
the  medium  of  the  sense  of  feeling.  Nor  is  this  all,  for 
even  the  sense  of  smell  becomes  a  valuable  assistant  to 
the  hand-turner.  Several  metals,  especially  wrought-iron. 
steel  and  brass,  emit  (when  cut  at  a  high  speed)  a  peculiar 
smell,  which  becomes  stronger  with  the  increase  in  the 
speed  at  which  they  are  cut  and  the  comparative  dul- 
ness  of  the  edge  of  the  tool  employed  to  cut  them,  more 
especially  when  the  cutting  edge  of  the  tool  is  supplied 
with  oil  during  the  operation  of  cutting.  The  reason  that 
this  sense  of  smell  becomes  more  appreciable  during  the 
operation  of  hand  than  during  that  of  slide  rest  turning, 
is  because  the  face  of  the  operator  is  nearer  to  the  work, 
and  because  hand-turning  is  performed  at  a  higher  rate 
of  cutting  speed. 

If  a  tool  for  use  in  a  slide  rest  is  too  keen  for  its  allotted 
duty,  the  only  result  under  ordinary  circumstances  is,  that 
it  will  jar  or  chatter  (that  is,  tremble  and  cut  numerous 
indentations  in  the  work),  or  that  it  will  loose  its  cutting 
edge  unnecessarily  soon.  But  a  hand  tool  possessing 
this  defect  will  in  many  instances  rip  into  the  work, 
because  the  power,  required  to  prevent  the  strain,  placed 
by  the  cut  upon  the  tool,  from  forcing  the  tool  deeper  into 
its  cut  than  is  intended,  is  too  great  to  be  sustained  by 
the  hand  ;  and  the  tool,  getting  beyond  the  manipulator's 
control,  rips  into  the  work,  cutting  a  gap  or  groove  in  it, 
and  perhaps  forcing  it  from  between  the  centres  of  the 


HAND-  TURNING.  153 

lathe.  If,  on  the  other  hand,  a  tool  is  of  such  a  form  that 
it  requires  a  pressure  to  keep  it  to  its  duty,  the  amount  of 
such  pressure,  when  the  tool  is  held  at  any  relative  height 
and  angle  to  the  horizontal  centre  line  of  the  work,  and 
the  variation  in  that  amount,  due  to  the  slightest  altera- 
tion of  the  shape  of  the  tool,  are  readily  appreciated  by 
sensitiveness  of  the  hand  ;  when  they  would  be  scarcely,  if 
at  all,  perceived  were  the  same  tool,  under  like  conditions, 
used  in  a  slide  rest. 

These  considerations,  together  with  the  great  advan- 
tage in  the  relative  rapidity  with  which  the  form  and 
applied  position  of  a  hand  tool  may  be  varied,  render 
hand-turning  far  more  instructive  to  a  beginner  than  any 
other  branch  of  the  machinist's  art. 

It  is  a  common  practice  to  centre  one  end  of  the  work 
only,  and  to  fasten  the  other  end  in  a  chuck,  thus  making 
the  chuck  serve  as  a  driver,  and  obviating  the  necessity 
of  centre-punching  more  than  one  end  of  the  work.  This 
method  will,  it  is  true,  save  a  little  time,  but  is  objec- 
tionable for  the  following  reasons:  Chucks  will  run  quite 
true  while  they  are  new,  and  indeed  for  some  little  time, 
but  they  do  in  time  get  out  of  true ;  and  as  a  result,  if  the 
work  requires  to  be  reversed  in  the  lathe  so  as  to  be 
turned  from  end  to  end,  the  part  of  the  work  turned 
during  the  second  chucking  will  be  eccentric  to  that  part 
turned  during  the  first  chucking.  If  one  end  only  of  the 
work  requires  to  be  turned,  and  needs  be  true  only  of 
itself,  and  irrespective  of  the  part  held  in  the  chuck,  the 
latter  may  be  employed;  this  subject  will,  however,  be 
treated  hereafter. 

Our  first  operation,  that  is,  truing  the  end  of  the  work, 
is  performed  with  a  side  tool,  of  which  there  are  two  kinds, 
both  being  made  of  three-cornered  (or  three-square,  as  it 
is  generally  termed)  steel,  the  only  point  of  difference 
being  in  the  manner  of  grinding  them.  A  worn-out  saw 
file  is  an  excellent  thing  to  make  a  side  tool  of,  because 


154  COMPLETE  PRACTICAL  MACHINIST. 

the  teeth  grip  the  rest  and  prevent  the  tool  from  slipping. 
It  is  not  necessary  to  soften  the  file  at  all,  but  (for  either 
kind)  merely  to  grind  it  so  as  to  make  one  edge  a  cutting 
one,  and  not  make  the  point  too  thin,  by  grinding  the  end 
off  a  trifle. 

If  the  cutting  edges  are  smoothed  by  the  application  of 
an  oilstone,  they  will  give  a  very  clean  and  smooth  polish 
to  the  work.  The  rest  should  be  set  at  such  a  height  that 
the  cutting  edge  of  the  tool  is  slightly  above  the  horizontal 
centre  of  the  work  ;  and  the  tool  should  be  so  held  that  its 
side  face  stands  nearly  parallel  with  the  end  face  of  the 
work,  the  cutting  edge  being  held  slightly  inclined  towards 
the  work,  which  will  give  to  the  tool  edge  the  necessary 
clearance.  Any  excess  of  this  inclination  renders  the  tool 
liable  to  turn  out  of  true,  and  destroys  its  cutting  edge 
very  rapidly. 

ROUGHING     OUT. 

Our  work,  being  countersunk,  is  now  ready  to  be  turned 
down  to  nearly  the  required  size  all  over,  before  any  one 
part  is  made  to  the  finished  size. 

From  what  has  been  said  in  another  place,  the  impor- 
tance (in  work  which  requires  to  be  kept  very  true)  of 
roughing  the  work  out  all  over  before  any  one  part  is 
finished  will  be  obvious,  since  the  breaking  of  the  skin  in 
any  one  part  releases  the  tension  on  that  part,  whatever  be 
the  temperature  it  is  under  when  in  operation.  It  is  not 
practicable,  on  lathe  work,  to  at  all  times  rough  the  work 
out  all  over  before  finishing  any  part ;  but  in  our  present 
operation,  of  turning  down  a  plain  piece  of  iron  held 
between  the  lathe  centres,  we  are  enabled  to  pursue  that 
course,  and  we  will  therefore  commence  the  roughing-out 
process  with  a  graver. 

THE    GRAVER 

is  formed  by  grinding  the  end  of  a  piece  of  square  steel  at 
an  angle  across  the  end,  giving  it  a  diamond-shaped 
appearance. 


HAND-TURNING.  155 

The  graver  is  the  most  useful  of  all  hand  tools  used 
upon  metals.  It  can  be  applied  to  either  rough  out  or 
finish  steel,  w rough t-iron,  cast-iron,  brass,  copper  or  other 
metal,  and  will  turn  work  to  almost  any  desired  shape. 
Held  with  a  heel  pressed  firmly  against  the  hand  rest  (the 
point  being  used  to  cut,  as  shown  in  Fig.  147,  A  being  the 
work,  B  the  graver,  and  C  the  lathe  rest),  it  turns  very 
true,  and  cuts  easily  and  freely.  This,  therefore,  is  the 
position  in  which  the  graver  is  held  to  rough  out  the 
work. 

Fig.  147. 


THE 


The  heel  of  the  graver,  which  rests  upon  the  hand  rest, 
should  be  pressed  firmly  to  the  rest,  so  as  to  serve  as  a 
fulcrum  and  at  the  same  time  as  a  pivotal  point  upon 
which  it  may  turn  to  follow  up  the  cut  as  it  proceeds. 
The  cutting  point  of  the  graver  is  held  at  first  as  much  as 
convenient  toward  the  dead  centre,  the  handle  in  which 
the  graver  is  fixed  being  held  lightly  by  both  hands,  and 
slightly  revolved  from  the  right  towards  the  left,  at  the 
same  time  that  the  handle  is  moved  bodily  from  the  left 
towards  the  right.  By  this  combination  of  the  two  move- 
ments, if  properly  performed,  the  point  of  the  graver  will 
move  in  a  line  parallel  to  the  centres  of  the  lathe, 
because,  while  the  twisting  of  the  graver  handle  causes  the 
graver  point  to  move  away  from  the  centre  of  the  diameter 
of  the  work,  the  moving  of  the  handle  bodily  from 


356  COMPLETE  PRACTICAL  MACHINIST. 

left  to  right  causes  the  point  of  the  graver  to  approach 
the  centre  of  that  diameter ;  hence  the  one  movement 
counteracts  the  other,  producing  a  parallel  movement, 
and  at  the  same  time  enables  the  graver  point  to  follow 
up  the  cut,  using  the  heel  as  a  pivotal  fulcrum,  and 
hence  obviating  the  necessity  of  an  inconveniently  fre- 
quent moving  of  the  heel  of  the  tool  along  the  rest.  The 
most  desirable  range  of  these  two  movements  will  be  very 
readily  observed  by  the  operator,  because  an  excess  in 
either  of  them  destroys  the  efficacy  of  the  heel  of  the 
graver  as  a  fulcrum,  and  gives  it  less  power  to  cut,  and 
the  operator  has  lesc  control  of  the  tool. 

The  handle  in  which  the  graver  is  held  should  be  suf- 
ficiently long  to  enable  the  operator  to  grasp  it  with  both 
hands  and  thus  to  hold  it  steadily,  even  though  the  work 
may  run  very  much  out  of  true. 

To   cut  smoothly,   as    is    required    in  finishing   work, 

Fig.  148.- 


the  graver  is  held  as  shown  in  Fig.  148,  moving  it  from 
place  to  place  along  the  work,  and  testing  it  for  parallel- 
with  the  calipers.  For  finishing  curves,  however, 


ism 


HAND-TURNING.  157 

the  end  face  of  the  graver  should  be  ground,  curved 
from  the  heel  to  the  point,  but  of  less  curvature  than  the 
work.  Even  parallel  work  should  be  finished  by  being 
filed  with  a  smooth  file  while  the  lathe  is  running  at  a 
high  speed.  As  little  as  possible  should,  however,  be  left 
for  the  file  to  do,  because  it  cuts  the  softer  veins  of  the 
metal  more  readily  than  the  rest,  and  therefore  makes  the 
work  out  of  true. 

For  use  on  brass  and  other  soft  metals,  the  two  top  flat 
sides  of  the  graver  should  be  ground  away  so  as  to  have  a 
negative  top  rake.  The  strain  on  the  tool,  when  cutting 
soft  metals,  is  comparatively  slight,  so  that  the  graver  is 
rarely  applied  to  such  metals  in  the  position  shown  iij 
Fig.  147. 

THE    HEEL   TOOL. 

In  those  exceptional  cases  in  which,  for  want  of  a  lathe 
having  a  slide  rest,  it  becomes  necessary  to  perform  com- 
paratively heavy  work  in  a  hand  lathe,  the  heel  tool 
should  be  employed.  This  tool  was  formerly  held  in 
great  repute,  but  has  become  less  useful  by  reason  of  the 
advent  and  universal  application  of  the  slide  rest.  It  is 
an  excellent  one  for  roughing  work  out,  and  will  take  a 
very  heavy  cut  for  a  hand  tool,  because  of  the  great 
leverage  it  possesses,  by  reason  of  its  shape  and  handle, 
over  the  work.  A  heel  tool  is  shown  in  Fig.  149,  A  being 
the  tool,  which  is  a  piece  of  square  bar  steel  forged  at  the 
end  to  form  the  cutting  edge.  The  body  of  the  square  part 
is  held  (in  a  groove  formed  in  the  wooden  handle  B)  by  an 
iron  strap  C,  which  is  tightened  by  screwing  up  the  under 
handle  D,  which  contains  a  nut  into  which  the  spindle 
of  the  strap  0  js  screwed  as  the  handle  D  is  revolved. 
The  heel  F  of  the  tool  is  tapered,  so  that  it  will  firmly 
grip  the  face  of  the  lathe  rest,  the  cutting  edge  E  being 
rounded  as  shown  in  Fig.  149.  The  tool  is  held  by 
grasping  the  handle  B  at  about  the  point  G,  with  the  left 
14 


158 


COMPLETE  PRACTICAL  MACHINIST. 


hand,  and  by  holding  the  under  handle  D  in  the  right 
hand,  the  extreme  end  H  of  the  handle  being  placed 
firmly  against  the  right  shoulder  of  the  operator.  The 
heel  F  of  the  tool  must  be  placed  directly  under  the  part 
of  the  work  it  is  intended  to  turn,  the  cutting  edge  E  of 
the  tool  being  kept  up  to  the  cut  by  using  the  handle  D 
as  a  lever,  and  the  heel  F  of  the  tool  as  a  fulcrum.  Not 
much  lateral  movement  must,  however,  be  allowed  to  the 
cutting  edge  of  the  tool  to  make  it  follow  the  cut,  as  it  will 
get  completely  beyond  the  manipulator's  control  and  rip 
into  the  work.  Until  some  knowledge  of  the  use  of  this 
tool  has  been  acquired,  it  is  better  not  to  forge  the  top  of 


Fig.  149. 


IDE  VIEW 


the  cutting  edge  E  too  high  from  the  body  of  the  tool  ; 
since  the  lower  it  is  the  easier  the  tool  is  to  handle. 

The  heel  tool  should,  like  the  graver,  be  hardened  right 
out;  but  in  dipping  it,  allow  the  heel  F  to  be  a  little  the 
softer  by  plunging  the  end  E  into  the  water  about  half 
way  to  F;  and  then,  after  holding  it  in  that  position  for 
about  four  seconds,  immerse  the  heel  F  also.  After  again 
holding  the  tool  still  for  about  six  seconds,  withdraw  it 
from  the  water  and  hold  it  until  the  water  has  dried  off 
the  point  E ;  dip  the  tool  again,  and  quickly  withdraw  it, 
repeating  this  latter  part  of  the  operation  until  the  tool  is 
quite  cold.  The  object  of  the  transient  dippings  is  to  pre- 


HAND-TURNING.  159 

vent  the  junction  of  the  hard  and  soft  metal  from  being  a 
narrow  strip  of  metal,  in  which  case  the  tool  is  very  liable 
to  break  at  that  junction.  The  tool  should  be  so  placed 
in  the  handle  that  there  is  only  sufficient  room  between 
the  cutting  edge  and  the  end  of  the  handle  to  well  clear 
the  lathe  rest,  and  should  be  so  held  that  the  handle 
stands  with  the  end  H  raised  slightly  above  a  horizontal 
position,  the  necessary  rake  being  given  by  the  angle  of 
the  top  face  at  E.  It  is  only  applicable  to  wrought-iron 
and  steel ;  but  for  use  on  those  metals,  especially  the  latter, 
it  is  a  superior  and  valuable  hand  tool. 

For  cutting  out  a  round  corner,  a  round-nosed  tool  of 
the  same  description  as  the  V  tool  given  for  starting 
threads  by  hand,  but  having  the  cutting  edge  ground 
round  instead  of  a  V  shape,  is  the  most  effective ;  it  will 
either  rough  out  or  finish,  and  may  be  used  with  or  with- 
out water,  but  it  is  always  preferable  to  use  water  for 
finishing  wrought-iron  and  steel.  This  is  a  sample  of  a 
large  class,  applicable  to  steel  and  wrought-iron,  the  metal 
behind  the  cutting  edge  being  ground  away  so  as  to  give 
to  the  latter  the  keenness  or  rake  necessary  to  enable  it  to 
cut  freely,  and  the  metal  behind  the  heel  being  ground 
away  to  enable  it  to  grip  the  rest  firmly. 

HAND-TURNING — BRASS   WORK. 

For  roughing  out  brass  work,  the  best  and  most  univer- 
sally applicable  tool  is  that  shown  in  Fig.  150,  which  is  to 

Fig.  150. 

10t>  VIEW 

Ji 


brass  work  what  the  graver  is  to  wrought-iron  or  steel. 
The  cutting   point   A   is   round-nosed.      The   hand    rest 


160  COMPLETE  PRACTICAL  MACHINIST. 

should  be  set  a  little  above  the  horizontal  centre  of  the 
work,  and  need  not  be  close  up  to  the  work,  because  com- 
paratively little  power  is  required  to  cut  brass  and  other 
soft  metals,  and  therefore  complete  control  can  be  had 
over  the  tool,  even  though  its  point  of  contact  with  the  rest 
be  some  little  distance  from  its  cutting  point,  which  allows 
a  greater  range  of  movement  of  the  tool  from  a  fixed 
point.  The  best  method  of  holding  and  guiding  is  to 
place  the  forefinger  of  the  left  hand  under  the  jaw  of  the 
hand  rest,  and  to  press  the  tool  firmly  to  the  face  of  the 
rest  by  the  thumb,  regulating  the  height  so  that  the  cut- 
ting is  performed  at  or  a  little  below  the  horizontal  centre 
of  the  work.  The  tool  point  may  thus  be  guided  with 
comparative  ease  to  turn  parallel,  taper,  or  round  or  hol- 
low curves,  or  any  other  desirable  shape,  except  it  be  a 
square  corner.  Nor  will  it  require  much  moving  upon  the 
face  of  the  lathe  rest,  because  its  point  of  contact,  being 
somewhat  removed  from  the  rest,  gives  to  the  tool  point  a 
comparatively  wide  range  of  movement.  The  exact  requis- 
ite distance  for  the  rest  to  be  from  the  work  must,  in  each 
case,  be  determined  by  the  depth  of  the  cut  and  the  degree 
of  hardness  of  the  metal ;  but  as  a  general  rule,  it  should  be 
as  distant  as  is  compatible  with  a  thorough  control  of  the 
tool.  The  cutting  end  of  this  tool  should  be  tempered  to  a 
light  straw  color. 

SCRAPERS. 

To  finish  brass  work,  various  shaped  tools,  termed 
scrapers,  are  employed.  The  term  scraper,  however, 
applies  as  much  to  the  manner  in  which  the  tool  is 
applied  to  the  work  as  to  its  shape,  since  the  same  tool 
may,  without  alteration,  be  employed  either  as  a  scraping 
or  a  cutting  tool,  according  to  the  angle  of  the  top  face 
(that  is,  the  face  which  meets  the  shavings  or  cuttings)  to 
a  line  drawn  from  the  point  of  contact  of  the  tool  with  the 
work  to  the  centre  line  of  the  work,  and  altogether  irre- 
spective of  the  angles  of  the  two  faces  of  the  tool  whose 


HAND-TURNING.  161 

junction  forms  the  cutting  edge.  To  give,  then,  the 
degree  of  angle  necessary  to  a  cutting  tool,  irrespective  of 
the  position  in  which  it  is  held,  is  altogether  valueless,  as 
will  be  readily  perceived. 

Scrapers  will  cut  more  freely  if  applied  to  the  work 
with  the  edges  as  left  by  the  grindstone;  but  if  they  are 
smoothed,  after  grinding,  by  the  application  of  an  oilstone, 
they  will  give  to  the  work  a  much  smoother  and  higher 
degree  of  finish.  They  should  be  hardened  right  out  for 
use  on  cast-iron,  and  tempered  to  a  straw  color  for  brass 
work.  If  the  scraper  jars  or  chatters,  as  it  will  sometimes, 
by  reason  of  its  having  an  excess  of  angle  or  bottom  rake, 
or  from  the  cutting  end  being  ground  too  thin,  a  piece  of 
leather,  placed  between  the  tool  and  the  face  of  the  rest, 
will  obviate  the  difficulty. 

Round  or  hollow  curves  may  be  finished  truly  and 
smoothly  by  simply  scraping ;  but  parts  that  are  parallel 
or  straight  upon  their  outer  surfaces  should,  subsequent  to 
the  scraping,  be  lightly  filed  with  a  smooth  file,  the  lathe 
running  at  a  very  high  speed  to  prevent  the  file  from  cut- 
ting the  work  out  of  true.  The  file  should,  however,  be 
kept  clean  of  the  cuttings  by  either  using  a  file  card  or 
cleaner,  or  by  brushing  the  hand  back  and  forth  on  the 
file,  and  then  striking  the  latter  lightly  upon  a  block 
of  wood  or  a  piece  of  lead,  the  latter  operation  being  much 
the  more  rapid,  and  sufficiently  effective  for  all  save  the 
Very  finest  of  work.  If  the  filings  are  not  cleaned  from  the 
file,  they  are  apt  to  get  locked  in  the  file  teeth  and  to  cut 
scratches  in  the  work.  To  prevent  this  the  file  may  be 
rubbed  with  chalk  after  every  eight  or  ten  strokes,  and  then 
cleaned  as  described.  After  filing  the  work,  it  may  be 
polished  with  emery  paper  or  emery  cloth.  The  finer  the 
paper  and  the  more  worn  it  is,  the  better  and  finer  will  be 
the  finish  it  will  give  to  the  work ;  for  all  metals  polish 
best  by  being  rubbed  at  a  high  speed  with  a  thin  film 
composed  of  fine  particles  of  their  own  nature,  as  ivory  is 


162  COMPLETE  PRACTICAL  MACHINIST. 

best  polished  by  ivory  powder,  and  wood  by  shavings 
cut  from  itself.  To  facilitate  obtaining  the  film  of  metal 
upon  the  emery  paper,  the  latter  may  be  oiled  to  a  very 
slight  extent,  by  rubbing  a  greasy  rag  over  it,  which 
will  cause  the  particles  it  at  first  cuts  to  adhere  to  its 
surface.  Crocus  cloth  is  the  best  for  highly  finishing  pur- 
poses, because  it  will  wear  longer  without  becoming  torn. 
It  should  be  pressed  hard  against  the  work,  and  reversed 
in  all  directions  upon  it,  so  as  to  wear  all  parts  of  its  sur- 
face equally,  and  to  distribute  the  metal  film  all  over; 
and  the  work  should  be  revolved  at  as  high  a  speed  as 
possible,  while  the  crocus  cloth,  during  the  first  part  of 
the  polishing,  is  kept  in  rapid  motion  upon  the  work  back- 
ward and  forward,  so  that  the  marks  made  upon  the  work 
by  the  emery  cloth  will  cross  and  recross  each  other. 
When  fine  finishing  is  to  be  performed,  the  crocus  cloth 
should  be  pressed  very  lightly  against  the  work  and  moved 
laterally  very  slowly. 

Kouud  or  hollow  corners,  or  side  faces  of  flanges,  of 
either  wrought  or  cast-iron  or  brass,  may  be  polished  with 
grain  emery  and  oil.  applied  to  the  work  on  the  end  of  a 
piece  of  soft  wood,  the  operation  being  as  follows:  The  end 
of  the  wood  to  which  the  oil  and  emery  is  to  be  applied 
should  be  slightly  disintegrated  by  being  bruised  with  a 
hammer;  this  will  permit  the  oil  and  emery  to  enter  into 
and  be  detained  in  the  wood  instead  of  passing  away  at 
the  sides,  as  it  otherwise  would  do,  thus  saving  a  large 
proportionate  amount  of  material.  The  wood,  being 
bruised,  will  also  conform  itself  much  more  readily  to  the 
shape  of  curves,  grooves,  or  corners.  The  hand  rest  is 
then  placed  a  short  distance  from  the  work,  and  the  piece 
of  wood  rests  upon  it,  using  it  as  a  fulcrum.  The  end  of 
the  wood  should  bear  upon  the  work  below  the  horizontal 
level  of  the  centre  of  the  latter,  so  that  depressing  the  end 
of  the  wood  held  in  the  hand  employs  it  as  a  lever,  placing 
considerable  pressure  against  the  work ;  and  the  distance 


HAND-TURNING.  163 

of  the  rest  from  the  work  allows  the  end  of  the  piece  of 
wood  to  have  a  reasonable  range  of  lateral  movement, 
without  being  moved  upon  the  face  of  the  lathe  rest.  The 
method  of  using  the  wood  is  the  same  as  that  employed  in 
using  emery  cloth,  except  that  it  must,  during  the  earlier 
stage  of  its  application,  be  kept  in  very  continuous  lateral 
movement,  or  the  grain  emery  will  lodge  in  any  small 
hollow  specks  which  may  exist  in  the  metal,  and  hence  cut 
small  grooves  in  the  work.  Another  exception  is  that  the 
finishing  must  be  performed  with  only  such  emery  as  may 
be  embedded  in  the  wood,  and  without  the  application  of 
any  oil ;  especially  are  these  directions  necessary  for  cast- 
iron  or  brass  work.  The  work  may  then  be  wiped  dry,  and 
an  extra  polish  imparted  to  it  by  the  application  of  fine 
or  worn  and  glazed  emery  cloth,  moved  slowly  over  its 
surfaces. 


CHAPTER   VIII. 

DRILLING   IN   THE   LATHE. 

WE  have  next  to  consider  drilling  tools  as  they  are  em- 
ployed in  the  lathe.  For  boring  very  small  holes,  as  in 
centre-drilling,  it  is  usual  and  advisable  to  revolve  the 
drill  and  use  the  dead  centre  and  its  gear  as  a  feed  motion. 
For  small  lathes,  a  small  chuck  or  face  plate  is  made,  it 
having  a  conical  stem  so  as  to  fit  into  the  hole  into  which 
the  dead  centre  fits. 

It  is  obvious  that,  as  a  lathe  possesses  no  facilities  for 
chucking  work  upon  the  tail  stock,  work  which  requires 
chucking,  or  is  too  heavy  to  be  held  conveniently  in  the 
hand,  can  only  be  drilled  in  the  lathe  by  being  chucked 
and  revolved,  the  drill  remaining  stationary,  and  fitted 
into  the  socket  in  the  tail  stock  spindle,  or  else  suspended 
by  being  held  by  the  work  at  the  cutting  end,  and  by 
the  dead  centre  at  the  other  end,  and  prevented  from 
revolving  by  the  aid  of  a  drilling  rest  or  a  wrench.  If  the 
work  revolves,  it  must  of  course  be  set  to  run  true ;  and 
eince  the  setting  involves  more  work  than  would  be 
required  to  hold  it  upon  a  drilling  machine  table,  it  fol- 
lows that  the  lathe  is  only  resorted  to  for  drilling  purposes 
in  cases  in  which  it  is  imperative  to  use  it.  These  instances 
may  be  classified  as  follows : 

1.  Those  in  which  very  straight  and  true  holes  are 
required,  and  in  which  the  point  of  ingress  and  egress  may 
be  centre-punched,  in  which  cases  (the  back  centre  of  the 
lathe  being  placed  in  the  centre  punch  mark,  and  the 
point  of  the  drill  in  the  other)  the  drilling  is  sure  to  be 

true. 

164 


DRILLING  IN  THE  LATHE.  165 

2.  Those  in  which  the  work  being  very  long,  can  be  got 
into  the  lathe  in  consequence  of  the  movable  tail  stock, 
when  it  could  not  be  got  into  the  drilling  machine. 

3.  Those   in  which,  there   being   turning   to   be   done 
besides  the  boring  or  drilling,  the  whole  may  be  performed 
in  the  lathe. 

4.  Those  in  which  the  holes  require  to  be  very  true,  the 
work  being  chucked  in  the  lathe. 

The  class  first  mentioned  refers  to  small  and  light  work 
only,  and  requires  no  comment,  save  that  the  work  should 
be  slowly  revolved  on  the  lathe  centre  while  the  drilling  is 
progressing,  so  that  the  work  will  not  drill  out  of  true  in 
consequence  of  its  weight.  The  second  was  referred  to 
under  the  heading  of  the  cone  plate,  or  cone  chuck,  as  it 
is  sometimes  termed ;  and  the  third  (which  usually  com- 
prises the  fourth)  we  will  proceed  to  discuss. 

The  spindle  in  the  tail  stocks  of  lathes  are  usually  pre- 
vented from  revolving  by  having  a  narrow  groove  along 
them,  into  which  a  small  lug,  stationary  with,  and  pro- 
jecting through,  the  bearing  of  the  spindle,  fits.  If,  there- 
fore, a  heavy  strain,  tending  to  twist  the  socket  (as  would 
be  the  case  if  a  drill  of  a  comparatively  large  size  were 
held  by  it),  is  placed  upon  it,  the  groove,  from  its  compar- 
atively small  wearing  surface,  soon  gets  worn  as  well  as 
the  lug,  and  the  edge  of  the  groove  bulges^  causing  the 
socket  to  bind  in  its  guide.  Tail  stock  spindles  are  not,  in 
fact,  usually  designed  to  perform  such  heavy  duty ;  hence 
it  is  an  error  to  assign  it  to  them,  unless,  as  is  the  case  in 
some  special  lathes,  the  tail  stock  spindles,  and  hence  their 
bearings,  are  made  square  to  suit  the  spindles  to  carry 
drills  for  heavy  duty.  For  ordinary  drilling  in  the  lathe 
the  twist  drill  is  employed,  but  since  it  is  used  in  the  drill- 
ing machine  also,  it  will  be  considered  in  connection  with 
other  drilling  tools,  and  we  may  therefore  pass  to  such 
tools  as  are  used  more  exclusively  on  lathe  work,  whether 
for  drilling  holes  out  of  the  solid  metal,  or  for  enlarging 


166 


COMPLETE  PRACTICAL  MACHINIST. 


holes  that  have  been  cast  or  forged  in  the  work  and  which 
are  used  upon  work  that  is  chucked  upon  the  face  plate  or 
in  other  chucking  devices. 


HALF   ROUND    BITS. 


For  drilling  or  boring  holes  very  true  and  parallel  in 
the  lathe,  the  half  round  bit  shown  in  Fig.  151  is  unsur- 
passed. 

Fig.  151. 


SIDE  VIEW 


The  cutting  edge  A  is  made  by  backing  off  the  end,  as 
denoted  by  the  space  between  the  lower  end  of  the  tool 
and  the  dotted  line  B,  and  performing  its  duty  along  the 
radius,  as  denoted  by  the  dotted  line  in  the  end  and  top 
views. 

It  is  only  necessary  to  start  the  half  round  bit  true,  to 
insure  its  boring  a  hole  of  any  depth,  true,  parallel,  and 
very  smooth.  To  start  it,  the  face  of  the  work  should,  if 


DRILLING  IN  THE  LATHE.  1(V7' 

the  centre  upou  which  the  tool  has  been  turned,  which 
line  will  form  a  guide  for  filing  the  top  face  down  to  make 
the  tool  of  the  required  thickness  of  one-half  of  its  diam- 
eter. The  edge  A  should  be  perfectly  square  with  the 
side  or  diametrical  edges  C  C.  The  circumference  of  the 
turned  part  should  have  the  turning  marks  effaced  with  a 
very  smooth  file,  by  draw-filing  the  work  lengthwise,  care 
being  taken  to  remove  an  even  quantity  all  over.  The 
rake  of  the  tool,  as  denoted  at  the  dotted  line  B,  should 
not  be  greater  in  proportion  than  is  there  shown. 

This  tool  should  be  tempered  to  a  straw  color  and  em- 
ployed at  a  cutting  speed  of  about  fifteen  feet  per  minute, 
and  fed  at  a  coarse  feed  by  hand.  For  use  on  parallel 
holes,  no  part  should  be  ground  save  the  end  face; 
whereas,  in  the  case  of  taper  ones,  the  top  face  may  be 
ground,  taking  a  little  off  as  will  answer  the  purpose.  It 
should  be  borne  in  mind  that,  as  the  steel  expands  (and 
therefore  becomes  larger  in  diameter)  by  the  process  of 
hardening,  the  necessary  allowance,  which  is  about  the 
one-fiftieth  of  an  inch  per  inch  of  diameter,  should  be 
made  when  turning  it  in  the  lathe.  Tools  of  this  descrip- 
tion, which  have  a  turned  part  to  guide  them,  or  those 
which  depend  upon  the  trueness  of  their  outline  or  cutting 
edges  to  make  them  perform  their  duty,  and  which  are 
apt,  in  the  process  of  hardening,  to  get  out  of  true  (for  all 
steel  alters  more  or  less  during  the  operation  of  harden- 
ing), may  be  made  true  after  the  hardening  or  tempering 
by  a  process  to  be  described  in  our  future  remarks  on 
reamers,  since  it  applies  more  directly  to  those  tools  than 
to  half  round  bits. 

Fig.  152. 


Fig.  152  represents  a   bit   in   which   a  segment  A  is 


168 


COMPLETE  PRACTICAL  MACHINIST. 


cut  out  to  admit  a  cutter  C,  which  may  be  adjusted  to  size 
by  slips  of  paper  put  in  at  C. 

Figs.  153  and  154  represent  a  side  and  an  end  view  of  a 


Fig,  153. 


Fig.  154. 


Fig.  155. 


Cutter 


cutter  and  bar  (and  Fig.  155  a  side  view  of  the  cutter 
removed  from  the  bar),  especially  designed  for  piercing 
holes  out  of  the  solid,  and  of  great  depth.  The  cutting 
edges  C  and  D  form  a  radial  line,  and  the  latter  does  not 
extend  to  the  centre.  As  a  result,  there 
is  formed  a  slightly  projecting  edge  to 
the  work,  which  acts  as  a  guide  to  keep 
the  cutter  true.  The  end  A  of  the 
cutter  fits  into  the  bore  of  the  bar,  and 
the  latter  is  provided  with  longitudinal 
grooves  G  H,  so  that  water  forced  th  rough 
the  bore  of  the  bar  will  wash  the  cuttings 
out  through  the  grooves  G  H. 

To  enlarge  holes  and  true  them  out, 
the  flat  drill  (Fig.  156)  is  employed.  It' 
is  an  ordinary  drill  made  out  of  flat  steel, 
having  pieces  of  hard  wood  fastened  to 
the  cutting  end,  A  being  the  steel,  and  B  B  pieces  of  wood, 
held  on  by  screws.  When  the  drill  has  entered  the  hole 
far  enough  to  make  it  of  the  diameter  of  the  drill,  the 


DRILLING  IN  THE  LATHE. 


169 


pieces  of  wood  enter  and  fit  the  hole,  steadying  the  drill 
and  tending  to  keep  it  true.  It  is  necessary,  however,  to 
true  out  the  hole  at  the  outer  end  before  inserting  the 
drill ;  for  if  the  drill  enters  out  of  true,  it  will  get  worse  as 
the  work  proceeds.  The  drill  is  fed  to  its  duty  by  the 
back  lathe  centre,  placed  in  the  centre  upon  which  the 
drill  has  been  turned  up. 

The  pieces  of  wood  should  be  affixed  before  the  drill  is 
turned  up,  and  so  trued  up  with  the  drill,  which  should 
then  be  lightly  draw-filed  on  the  sides;  and  the  cutting 
end  having  the  necessary  rake  filed  upon  it,  should  be 

Fig.  156. 


tempered  to  a  straw  color,  the  pieces  of  wood  being,  of 
course,  temporarily  removed.  For  use  on  conical  holes, 
the  sides  must  be  made  of  the  requisite  cone  and  the 
cutting  speed  in  that  case  reduced  (in  consequence  of  the 
broad  cutting  surface)  to  about  10  feet  per  minute.  (This 
speed  will  also  serve  in  boring  conical  holes  with  a  half 
round  bit.)  Such  a  drill  is  an  excellent  tool  for  ordinary 
work,  such  as  pulleys,  etc.,  because  it  will  perform  its  duty 
very  rapidly  and  maintain  its  standard  size ;  and  it  re- 
quires but  little  skill  in  handling.  It  is  more  applicable, 
however,  to  cast-iron  than  to  any  other  metal.  After  the 
outer  end  of  the  hole  has  been  turned  true  and  of  the 
required  size,  to  receive  the  drill,  and  when  the  latter  is 
15 


170 


COMPLETE  PRACTICAL  MACHINIST. 


inserted  for  operation,  it  is  an  excellent  plan  to  fasten  a 
piece  of  metal,  such  as  a  lathe  tool,  into  the  tool  post,  and 
adjust  the  rest  so  that  the  end  of  the  tool  has  light  contact 
with  the  drill,  so  as  to  steady  it.  The  lathe  should  be 
started,  and  the  tool  end  wound  in  by  the  screw  of  the 
rest,  until,  the  drill  being  true,  the  tool  end  just  touches  it, 
and  having  its  end  bevelled  so  as  to  have  contact  with  the 
drill  as  close  to  the  entrance  of  the  hole  as  possible,  in 
which  position  it  is  most  effective.  In  all  cases,  when  a  drill 
is  used  in  the  lathe  and  remains  stationary  while  the  work 
revolves,  this  steadying  implement  should  be  employed, 
since  it  operates  greatly  to  correct  any  tendency  of  the 
drill  to  spring  out  of  true. 

To    hold  flat  drills,  or  those  having  square  ends,  and 
prevent   them   from    revolving,  a    drill  holder     may    be 

Fig.  157. 


employed,  either  at  the  front  end   of  the  drill  immedi- 
ately behind  the  wood,  or  at  the  other  end  near  the  dead 


DRILLING  IN  THE  LATHE. 


171 


centre,  the  shape  of  the  holder  being  as  shown  in  Fig.  157, 

which  shows  five  sizes.     The  angle  of  the  eye 

to  the  body  of  the  bar  being  so  that  the  slide    Fig.  158. 

rest  will  stand  off  and  not  be  close  up  to  the 

chuck  plate  or  the  end  of  the  work.     It  is 

well  to  keep  the  eye  of  the  drill  holder  close 

to  the  entrance  of  the  hole  being  drilled. 


REAMERS. 

The  reamer  consists  of  a  hardened  piece 
of  steel,  fluted  as  shown  in  Fig.  158,  so  as  to 
produce  cutting  edges  at  the  tops  of  the  flutes. 
It  is  revolved  and  forced  endways  into  the 
work. 

The  reamer  owes  its  present  state  of  per- 
fection to  the  emery-wheel,  which  grinds  it 
true  after  the  hardening  process,  and  the 
main  considerations  in  determining  its  form 
are  as  follows : 

1.  The  number  of  its  cutting  edges. 

2.  The  spacing  of  the  teeth. 

3.  The  angles  of  the  faces  forming  the  cut- 
ting edges. 

4.  Its  maintenance  to  standard  diameter. 
As   to   the   first,  it   is   obvious   that  the 

greater  the  number  of  cutting  edges  the  more 
lines  of  contact  there  are  to  steady  it  on  the 
walls  of  the  hole;  but  in  any  case  there 
should  be  more  than  three  teeth,  for  if  three 
teeth  are  used,  and  one  of  them  is  either  re- 
lieved of  its  cut,  or  takes  an  excess  of  cut 
by  reason  of  imperfections  in  the  roundness 
of  the  hole,  the  other  two  are  similarly  af- 
fected and  the  hole  is  thus  made  out  of  round. 
As  to  the  spacing  of  the  teeth,  it  is  determined  to  a  great 


172 


COMPLETE  PRACTICAL  MACHINIST. 


extent  by  the  size  of  the  reamer  and  the  facilities  that  size 
affords  for  grinding  the  reamer. 

The  method  employed  to  grind  a  reamer  is  shown  in 
Fig.  159,  in  which  is  represented  a  rapidly  revolving 
emery-wheel,  a  reamer,  and  also  a  gauge  against  which 
the  front  face  of  each  tooth  is  held  while  its  top  or  cir- 
cumferential face  is  being  sharpened.  The  reamer  is 
held  true  to  its  axis,  and  is  pushed  endways  beneath  the 
revolving  emery-wheel.  In  order  that  the  wheel  may 
leave  the  right-hand  or  cutting  edge  the  highest  (as  it 
must  be  to  enable  it  to  cut),  the  centre  of  the  emery-wheel 

Fig.  159. 


REAMER 

must  be  on  the  left  hand  of  that  of  the  reamer,  and  the 
spacing  of  the  teeth  must  be  such  that  the  periphery  of 
the  emery-wheel  will  escape  tooth  B,  for  otherwise  it 
would  grind  away  its  cutting  edge.  It  is  obvious,  how- 
ever, that  the  less  the  diameter  of  the  emery-wheel,  the 
closer  the  teeth  may  be  spaced  ;  but  there  is  an  objection 
to  this,  inasmuch  as  that  the  top  of  the  tooth  is  naturally 
ground  to  the  curvature  of  the  wheel,  as  is  shown  in  Fig. 
160,  in  which  two  different-sized  emery-wheels  are  repre- 
sented, operating  on  the  same  diameter  of  reamer.  The 
cutting  edge  of  A  has  the  most  clearance,  and  is  therefore 
the  weakest  and  least  durable;  hence  it  is  desirable  to 


173 


GRINDING  REAMERS. 


employ  as  large  a  wheel  as  the  spacing  of  the  teeth 
allow,  there  being  at  least  four  teeth,  and  preferably  six, 
on  small  reamers,  and  their  number  increasing  with  the 
diameter  of  the  reamer. 


Fig.  160, 


Concerning  the  angles  of  the  faces  forming  the  cutting 
edges,  it  is  found  that  the  front  faces,  as  A  and  B  in  Fig. 


Fig.  161. 


161,  should  be  a  radial  line,  for,  if  given  rake  as  at  C,  the 
tooth  will  spring  off  the  centre  at  point  E  in  the  direction 
of  D,  and  cause  the  reamer  to  cut  a  hole  of  larger  diameter 

r>* 


174  COMPLETE  PRACTICAL  MACHINIST. 

than  itself,  an  action  that  is  found  to  occur  to  some  extent 
even  where  the  front  face  is  a  radial  line.  As  this  spring 
augments  with  any  increase  of  cut-pressure,  it  is  obvious 
that  if  a  number  of  holes  are  to  be  reamed  to  the  same 
diameter,  it  is  essential  that  the  reamer  take  the  same 
depth  of  cut  in  each,  so  that  the  tooth-spring  may  be 
equal  for  each.  The  clearance  at  the  top  of  the  teeth  is 
obviously  governed  by  the  position  of  the  reamer  with  re- 
lation to  the  wheel,  and  the  diameter  of  the  wheel,  being 
less  in  proportion  as  the  reamer  is  placed  farther  beneath 
the  wheel,  and  the  wheel  diameter  is  increased.  In  some 
forms  of  reamer  the  teeth  are  formed  by  circular  flutes, 
such  as  at  H  in  Fig.  161,  and  but  three  flutes  are  used. 
This  leaves  the  teeth  so  strong  and  broad  at  the  base  that 
the  teeth  are  not  so  liable  to  spring;  but,  on  the  other 
hand,  the  clearance  is  much  more  difficult  to  produce  and 
to  grind  in  the  resharpening;  hence  such  reamers  have 
not  found  favor  in  the  United  States. 

As  to  the  maintenance  of  the  reamer  to  standard  diam- 
eter, it  is  a  matter  of  great  importance,  for  the  following 
reasons :  The  great  advantage  of  the  standard  reamer  is 
to  enable  holes  to  be  made  and  pieces  to  be  turned  to  fit 
in  them  without  requiring  any  particular  piece  to  be  fitted 
to  some  particular  hole,  and  in  order  to  accomplish  this  it 
is  necessary  that  all  the  holes  and  all  the  pieces  be  exactly 
alike  in  diameter.  But  the  cutting  edges  of  the  reamer 
begin  to  wear — and  the  reamer  diameter,  therefore,  to 
reduce — from  the  very  first  hole  it  reams,  and  it  is  only 
a  question  of  time  when  the  holes  will  become  too  small 
for  the  turned  pieces  to  enter  or  fit  properly.  In  all  pieces 
that  are  made  a  sliding  or  a  working  fit,  as  it  is  termed 
when  one  piece  moves  upon  the  other,  there  must  he 
allowed  a  certain  latitude  of  wear  before  the  one  piece  must 
be  renewed. 

One  course  is  to  make  the  reamer,  when  new,  enough 
larger  than  the  proper  size,  to  bore  the  holes  as  muHi 


ADJUSTABLE  REAMERS. 


175 


• 


larger  as  this  limit  of  wear,  and  to  restore  Fig.  162. 
it  to  size  when  it  has  worn  down  so  that  the 
holes  fit  too  tightly  to  the  pieces  that  fit 
them.  But  this  plan  has  the  great  disad- 
vantage that  the  pieces  generally  require  to 
have  other  cutting  operations  performed  on 
them  after  the  reaming,  and  to  hold  them  for 
these  operations  it  is  necessary  to  insert  in 
them  tightly  fitting  plugs,  or  arbors,  as  they 
are  termed.  If,  therefore,  the  holes  are  not  of 
equal  diameter,  the  arbor  must  be  fitted  to 
the  holes,  whereas  the  arbor  should  be  to 
standard  diameter  to  save  the  necessity  of 
fitting,  which  would  be  almost  as  costly  as 
fitting  each  turned  piece  to  its  own  hole.  It 
follows,  therefore,  that  the  holes  and  arbors 
should  both  be  made  to  a  certain  standard, 
and  the  only  way  to  do  this  is  to  so  construct 
the  reamer  that  it  may  be  readily  adjusted 
to  size  by  moving  its  teeth,  a  reamer  so  con- 
structed being  shown  in  Fig.  162.  The 
stock  is,  it  will  be  seen,  provided  with  dove- 
tail grooves  that  are  deepest  towards  the 
point,  so,  that  by  moving  the  teeth  towards 
the  shank,  their  diameter  is  increased. 

Fig.  163  represents  an  adjustable  reamer 
for  very  small  work.  It  is  pierced  with  a 
tapped  hole  and  countersunk,  and  is  split 
through  at  the  end.  A  small  plug  P  is  in- 
serted, and  a  screw  S,  and  it  is  obvious  that 
by  screwing  in  the  plug,  and  then  the  screw, 
the  diameter  of  the  reamer  is  enlarged.  The 
pressure  between  the  plug  P  and  screw  S 
serves  to  lock  the  latter  in  its  adjusted  posi- 
tion. It  is  obvious  that  the  split  weakens 
the  reamer,  hence  it  is  only  suitable  for  finishing  to  size. 


176 


COMPLETE  PRACTICAL  MACHINIST. 


SHELL    REAMERS. 

Shell  reamers,  such  as  shown  in  Fig.  164,  are  excellent 
tools  for  sizing  purposes;  that  is,  for  taking  a  very  light 
cut  intended  merely  to  smooth  out  the  hole,  and  insure 
correctness  in  iis  bore  or  size.  The  notch  fits  a  pin  in  the 
mandril  and  prevents  it  from  slipping  upon  the  mandril 
as  it  is  otherwise  very  apt  to  do. 

In  the  adjustable  reamer,  shown  in  Fig.  165,  A  repre- 
sents the  stock  and  D  the  cutter,  C  being  a  regulating 
washer,  and  D  and  E  the  tightening  nut  and  washer. 
Each  of  the  cutters  B  fits  into  a  dovetail  and  taper 


Fig.  163. 


groove  in  the  stock,  the  shallow  end  of  the  groove  being 
at  the  cutting  end  ;  so  that  if  the  regulating  washer  C  is 
reduced  in  width,  the  cutters  will  slide  forward  and  en- 
large in  diameter.  The  washer  C  is  thus  a  means  of 

adjusting   the  diameter 
Ftg.  1 64.  Of    the     cutters ;     and 

when  the  same  is  once 
adjusted,  the  nut  D  will 
lock  it  always  to  that 
precise  diameter.  If, 
therefore,  several  sets 
of  cutters  of  different 
heights  are  fitted  to  one 
stock,  and  turned  up  while  in  the  stock  to  the  requisite 
diameter  with  the  washer  C  in  its  place,  we  have  a  set  of 
standard  cutters  which  mav  always  be  placed  in  position 


ADJUSTABLE   REAMERS. 


177 


and  locked  up  by  the  nut  D,  without  measurement,  since 
their  sizes  cannot  vary.  By  providing  another  washer, 
very  slightly  thicker  than  the  standard,  the  reamer  will, 
in  the  case  of  each  set  of  cutters,  bore  a  hole  to  a  driving 
fit,  while  a  washer  a  trifle  thinner  will  cause  the  cutters  to 
bore  a  hole  of  an  easily  working  fit.  Thus  the  sizes  of 
the  cutters  are  regulated  by  the  washer  C,  and  not  by 
measurement  by  the  workman  ;  they  are  therefore  at  all 

Fig.  165. 


times  positive  and  equal.  The  cutters  are  backed  off  on 
the  ends  only,  their  tops  being  merely  lightly  draw-filed 
after  being  turned  up,  or  they  may  be  left  one  thirty- 
second  of  an  inch  too  large,  and  ground  ofT  after  harden- 
ing, by  the  grinding  process  already  described.  The 
cutters  should  be  forged  of  the  best  cast-steel  and  tem- 
nered  to  a  straw  color. 


CHAPTER    IX. 

BOKING     BARS. 

THE  boring  bar  is  one  of  the  most  important  tools  to  be 
found  in  a  machine  shop,  because  the  work  it  has  to  per- 
form requires  to  be  very  accurately  done ;  and  since  it  is  a 
somewhat  expensive  tool  to  make,  and  occupies  a  large 
amount  of  shop  room,  it  is  necessary  to  make  one  size  of 
boring  bar  answer  for  as  many  sizes  of  hole  as  possible, 
\vhich  end  can  only  be  attained  by  making  it  thoroughly 
stiff  and  rigid.  To  this  end  a  large  amount  of  bearing 
and  close  fitting,  using  cast-iron  as  the  material,  are 
necessary,  because  cast-iron  does  not  spring  or  deflect 
so  easily  as  wrought-iron  ;  but  the  centres  into  which  the 
lathe  centres  fit  are,  if  of  cast-iron,  very  liable  to  cut  and 
shift  their  position,  thus  throwing  the  bar  out  of  true.  It 
is,  therefore,  always  preferable  to  bore  and  tap  the  ends  of 
such  bars,  and  to  screw  in  a  wrought-iron  plug,  taking 
care  to  screw  it  in  very  tightly,  so  that  it  shall  not  at  any 
time  become  loose.  The  centres  should  be  well  drilled 
and  of  a  comparatively  large  size,  so  as  to  have  surface 
enough  to  suffer  little  from  wear,  and  to  well  sustain  the 
weight  of  the  bar.  The  end  surface  surrounding  the 
centres  should  be  turned  off  quite  true  to  keep  the  latter 
from  wearing  away  from  the  high  side,  as  they  would  do 
were  one  side  higher  than  the  other. 

The  smaller  sizes  of  boring  bars  are  usually  simple  par- 
allel mandrils,  having  slots  running  through  them,  into 
which  slots  or  key  ways  the  cutters  are  fitted,  being  fast- 
ened by  means  of  wedges.  The  backs  of  the  cutters  are 
tapered  to  the  same  degree  as  is  the  wedge,  so  that  the  key 
178 


SORING  BAPS.  179 

will  bear  evenly  along  both  the  edge  of  the  keyway  and 
the  cutter.  It  is  obvious  that,  if  the  cutter  is  turned  up 
in  the  bar,  and  is  of  the  exact  size  of  the  hole  to  be  bored, 
it  will  require  to  stand  true  in  the  bar,  and  will  therefore 
be  able  to  cut  on  both  ends,  in  which  case  the  work  may 
be  fed  up  to  it  twice  as  fast  as  though  only  one  edge  were 
performing  duty.  To  facilitate  setting  the  cutter  quite 
true,  a  flat  and  slightly  taper  surface  should  be  filed  on 
the  bar  at  each  end  of  the  keyway,  and  the  cutter  should 
have  a  recess  filed  in  it  to  fit  the  diameter  of  the  bar  so  filed, 
so  that  after  passing  the  cutter  through  the  slot,  it  may  be 
pushed  forward  in  the  manner  of  a  jib,  and  then  locked  by 
the  wedge.  Such  cutters  not  being  adjustable,  their  diamet- 
rical edges  need  not  have  any  clearance  or  rake  on  them, 
but  the  cutting  corners  should  be  rounded  off,  and  the  rake 
put  on  the  end  face  of  the  cutter  and  carried  around  the 
round  corner,  the  advantage  being  that  the  diametrical 
edge  of  the  cutter  will  bear  lightly  against  the  bore  of  the 
work,  and  prevent  the  bar  from  springing. 

Boring  bar  cutters,  required  to  be  adjustable,  must  not 
be  provided  with  a  recess,  but  must  be  left  plain,  so  that 
they  may  be  made  to  extend  out  on  one  side  of  the  bar  to 
cut  any  requisite  size  of  bore;  it  is  far  preferable,  however, 
to  employ  the  recess  and  have  a  sufficient  number  of  cut- 
ters to  suit  any  size  of  hole,  since,  as  already  stated  (there 
being  in  that  case  two  cutting  edges  performing  duty),  the 
work  may  be  fed  up  twice  as  fast  as  in  the  former  case,  in 
which  only  one  cutting  edge  operates.  This  description  of 
bar  for  use  on  small  holes  or  bores  is  simply  a  mandril, 
and  may  be  provided  with  several  slots  or  keyways  in 
its  length,  to  facilitate  facing  off  the  ends  of  work  which 
requires  it.  Since  the  work  is  fed  to  the  cutter,  it  is 
obvious  that  the  bar  must  be  at  least  twice  the  length  of 
the  work,  because  the  work  is  all  on  one  side  of  the  cut- 
ter at  the  commencement,  and  all  on  the  other  side  at 
the  conclusion  of  the  boring  operation.  The  excessive 


3.80  COMPLETE  PRACTICAL  MACHINIST. 

length  of  bar,  thus  rendered  necessary,  is  the  principal 
objection  to  this  form  of  boring  bar,  because  of  its  liability 
to  spring.  There  should  always  be  a  key  way,  slot,  or 
cutter  way  in  the  exact  centre  of  the  length  of  the  bar,  so 
as  to  enable  it  to  bore  a  hole  as  long  as  possible  in  pro- 
portion to  the  length  of  the  boring  bar,  and  a  keyway  or 
cutter-way  at  each  end  of  the  bar,  for  use  in  facing  off.  If, 
however,  a  boring  bar  is  to  be  used  for  a  job  which  does 
not  require  to  be  faced  off  at  the  ends,  the  keyway  should 
be  placed  in  such  a  position  in  the  length  of  the  bar  as 
will  best  accommodate  the  work,  and  should  then  be  made 
tapering  in  diameter  from  the  keyway  to  the  ends,  a  short 
piece  at  one  end  of  the  bar  being  made  parallel  to  receive 
the  driving  clamp.  A  lug,  however,  by  which  to  drive 
the  bar,  is  sometimes  cast  on  one  end.  This  form  of  bar 
is  stronger  in  proportion  to  its  weight,  and  therefore  less 
liable  to  spring  from  the  cut  or  to  deflect  than  is  a  parallel 
bar.  The  deflection  of  a  bar,  the  length  of  which  is  exces- 
sive in  proportion  to  its  diameter,  is  sufficient  to  cause  it 
to  bore  a  hole  out  of  straight  in  the  direction  of  the 
length  of  the  bore,  providing  that  the  cutter  is  not  recessed 
and  does  not  cut  on  both  sides — that  is  to  say,  when  the 
cutter  has  the  diametrical  bearing  against  the  diameter  of 
the  hole,  they  serve  to  steady  the  bar  and  prevent  it  from 
either  springing  away  from  the  cut,  or  from  deflecting  in 
consequence  of  its  own  weight.  The  question  of  spring 
affects  all  boring  bars ;  but  in  those  which  are  used  verti- 
cally, the  deflection  is  of  course  obviated. 

Here  it  may  be  mentioned  that  no  machine  using  a 
boring  bar  should  be  allowed  to  stop  while  the  finishing 
cut  is  being  taken,  for  the  following  reasons  :  The  friction, 
due  to  the  severance  of  the  metal  being  cut,  causes  it  to 
heat  to  a  slight  degree,  and  to  therefore  expand  to  an 
appreciable  extent;  so  that  when  the  cutter  makes  its  first 
revolution,  it  is  operating  upon  metal  at  its  normal  tem- 
perature, but  the  heat  created  has  expanded  the  bore  of 


BORING  BARS.  18i 

the  work,  and  hence  the  cut  taken  by  the  second  revolu- 
tion of  the  cutter  will  be  slightly  less  in  diameter.  This 
heating  and  expanding  process  continues  as  the  cutting 
proceeds,  so  that  if  (after  the  cutter  has  made  any  num- 
ber of  revolutions)  the  bar  is  stopped  and  the  cylinder  or 
other  work  being  bored  becomes  cool,  when  the  cutter 
makes  the  next  revolution  it  will  be  operating  upon  the 
bore  unexpanded  by  the  heat,  and  hence  will  cut  deeper 
into  the  metal,  until  the  metal,  being  reheated  by  the  cut 
during  the  revolution,  the  boring  proceeds  upon  expanded 
metal  as  before  the  stoppage  ;  thus  arresting  the  continu- 
ous progress  of  the  cutter  will  have  caused  the  cutting  of 
a  groove  in  the  bore.  Boring  bars,  for  use  in  bores  of  a 
large  diameter,  are  made  with  a  head  of  increased  diam- 
eter, the  body  of  the  bar  being  turned  along  its  length 
and  provided  with  a  slot  or  key  groove  from  end  to  end, 
the  sliding  head  is  bored  to  fit  the  bar,  and  is  provided 
with  a  keyway.  Thus  the  head  may  be  keyed  to  the  bar 
at  any  part  of  the  length  of  the  latter.  Several  cutters 
may  be  provided  to  the  head,  so  that  the  work  may  be  fed 
up  rapidly;  in  such  case,  however,  great  exactitude  is 
required  in  setting  them,  because  there  is  no  practical 
method  of  making  them  with  a  recess  to  insure  their  even 
projection  from  the  bar,  since  the  cutters  are  narrow,  and 
generally  cut  across  the  whole  diametrical  face,  so  that 
each  grinding  affects  their  distance  from  the  bar,  and 
hence  the  size  they  bore. 

A  rude  form  of  head  may  be  made  by  simply  cutting  a 
slot  or  slots  across  it,  and  fastening  the  tool  or  tools 
therein,  by  means  of  wedges,  and  packing  pieces,  if  neces- 
sary. The  only  advantage  possessed  by  this  kind  of  bar 
is  that  it  will  bore  a  round  hole,  even  though  the  bar  may 
run  out  of  true,  by  reason  of  either  or  both  of  the  centres 
being  misplaced,  or  even  though  the  bar  itself  may  have 
become  bent  in  its  length.  In  addition,  however,  to  its 
disadvantage  as  to  excessive  length,  it  possesses  the  further 
16 


182  COMPLETE  PRACTICAL  MACHINIST. 

one  that,  unless  a  line  drawn  from  the  two  centres  upon 
whicli  it  revolves  is  parallel  both  perpendicularly  and 
horizontally  to  the  lathe  bed,  the  hole  bored  will  be  oval 
and  not  round ;  or  if  the  bar  is  not  parallel  horizontally 
with  the  shears,  the  hole  will  be  widest  perpendicularly, 
and  vice  versa.  To  remedy  these  defects,  we  have  the 
boring  bar  with  the  feeding  head,  which  is  similar  to  that 
described,  save  that  the  work  remains  stationary  while  the 
cutters  are  fed  to  the  work  by  operating  the  head  along 
the  bar,  which  is  accomplished  as  follows:  either  along 
the  keyway  or  groove,  or  else  through  and  along  the  centre 
of  the  boring  bar,  there  is  provided  a  feeding  screw,  pass- 
ing through  a  nut  which  is  attached  to  the  sliding  head. 
As  the  bar  revolves  upon  its  axis,  the  screw  is,  by  means  of 
suitable  gearing,  caused  to  revolve  upon  its  own  axis,  as 
well  as  around  the  axis  of  the  bar,  thus  winding  the  head 
along  the  length  of  the  bar,  and  thus  feeding  it  to  the  cut. 
If  the  screw  runs  along  the  centre  of  the  bar,  it  is  usually 
operated  by  gear  wheels,  the  movement  of  the  feed  being 
continuous  at  all  parts  of  the  revolution  ;  but  if  the  screw 
is  contained  in  a  groove  cut  in  the  circumference  of  the 
bar,  a  common  star  feed  may  be  attached  to  the  end  of  the 
bar,  in  which  case  the  feed  of  the  whole  revolution  is  given 
to  the  sliding  head  during  that  portion  only  of  the  revo- 
lution in  which  the  outer  arm  of  the  star  is  moved  by  the 
projecting  bolt  or  arm  which  operates  it.  From  these 
directions,  it  will  be  readily  perceived  that  a  bar  of  the  lat- 
ter form,  but  having  the  screw  in  its  centre,  is  the  most 
preferable.  Care  must  be  taken,  however,  to  keep  these  bars 
running  quite  true ;  for  should  either  centre  run  out  of 
true,  the  hole  bored  will  be  larger  in  diameter  at  that  end  ; 
while  on  the  o*her  hand,  should  the  bar  become  bent  so  as 
to  run  out  of  true  in  the  middle  of  its  length,  the  hole 
bored  will  be  large  in  the  middle  if  the  work  was  chucked 
in  the  middle  of  the  length  of  the  bar;  and  otherwise  it 
will  be  larger  at  one  end. 


BORING  BAES.  183 

A  very  important  consideration  with  reference  to  boring 
bars  is  the  position  which  the  cutters  should  occupy 
towards  the  head  or  the  body  of  the  bar.  We  have 
already  been  over  the  same  ground  with  reference  to  part- 
ing or  grooving  tools  for  lathe  work,  cutting  tools  for 
planing  work,  and  cutters  for  cutting  out  holes  of  a  large 
diameter  in  boiler  plates ;  but  there  are  so  many  principles 
involved  in  the  shape  and  holding  position  of  cutting 
tools,  so  many  variations,  and  so  many  instances  in  which 
the  reasons  for  the  adoption  or  variation  of  a  principle  are 
not  obvious,  that  it  is  of  vital  importance  to  specify,  in  the 
case  of  each  tool,  its  precise  shape  and  position  of  applica- 
tion, together  with  the  reasons  therefor,  the  field  of  appli- 
cation being  so  extensive  that  the  memory  can  hardly  be 
relied  upon.  A  careful  survey  of  all  the  tools  thus  far 
treated  upon  will  disclose  that,  in  each  case  wherein  the 
cutting  edge  stands  in  advance  (in  the  direction  in  which 
the  tool  is  moving,  or,  if  the  work  move,  in  the  direction 
of  the  metal  to  be  cut)  of  the  fulcrum  upon  which  the  tool 
is  held,  the  springing  of  the  tool  causes  it  to  dig  into  the 
work,  deepening  the  cut,  and  in  most  cases  causing  the 
tool  point  or  cutting  edge  to  break;  while  in  every  instance 
this  defect  has  been  cured  (upon  tools  liable  to  spring)  by 
so  bending  or  placing  the  tool  that  the  fulcrum  upon 
which  it  was  held  stood  in  advance  of  the  cutting  edge; 
and  these  rules  are  so  universal  that  it  may  be  said  that 
pushing  a  tool  renders  it  liable  to  spring  into  the  work, 
and  pulling  it  or  dragging  it  enables  it  to  take  a  greater 
cut  and  to  spring  away  from  excessive  duty  ;  and  thus  the 
latter  prevents  breakage  and  excessive  spring,  because, 
when  the  spring  deepens  the  cut,  it  increases  proportion- 
ally the  causes  of  the  spring,  and  creates  a  contention 
between  the  strength  of  the  tool  and  the  driving  power  of 
the  machine,  resulting  in  a  victory  for  the  one  or  the 
other,  unless  the  work  itself  should  give  way,  either  by 
springing  away  from  the  tool  and  bending,  or  forcing  it 
from  the  lathe  centres  or  from  the  clampi  which  hold  it. 


184 


COMPLETE  PRACTICAL  MACHINIST. 


For  instance,  in  Fig.  166  is  shown  A,  a  boring  bar;  B  B 
is  the  sliding  head  ;  C  C  is  the  bore  of  the  cylinder,  and  1, 
2,  and  3  are  tools  in  the  positions  shown.  D  D  D  are  pro- 
jections in  the  bore  of  the  cylinder,  causing  an  excessive 
amount  of  duty  to  be  placed  upon  the  cutters,  as  sometimes 
occurs  when  a  cut  of  medium  depth  has  been  started. 
Such  a  cut  increases  on  one  side  of  the  bore  of  the  work 
until,  becoming  excessive,  it  causes  the  bar  to  tremble  and 

Fig '.166. 


the  cutters  to  chatter.  In  such  a  case,  tool  and  position 
No.  1  would  not  be  relieved  of  any  duty,  though  it  spring  to 
a  considerable  degree ;  because  the  bar  would  spring  in  the 
direction  denoted  by  the  dotted  line  and  arrow  E,  while 
the  spring  of  the  tool  itself  would  be  in  the  direction  of 
the  dotted  line  F.  The  tendency  of  the  spring  of  the  bar 
is  to  force  the  tool  deeper  into  the  cut  instead  of  relieving 
it;  while  the  tendency  of  the  spring  of  the  tool  will 
scarcely  affect  the  depth  of  the  cut.  Tool  and  position  No. 
2  would  cause  the  bar  to  spring  in  the  direction  of  the 
dotted  line  and  arrow  G,  and  the  tool  itself  to  spring  in 
the  direction  of  H,  the  spring  of  the  bar  being  in  a  direc- 


BORING  BARS. 


185 


tion  to  increase,  and  that  of  the  tool  to  diminish,  the  cut. 
Tool  and  position  No.  3  would,  however,  place  the  spring 
of  the  bar  in  a  direction  which  would  scarcely  affect  the 
depth  of  the  cut,  while  the  spring  of  the  tool  itself  would 
be  in  a  direction  to  give  decided  relief  by  springing  away 
from  its  excessive  duty.  It  must  be  borne  in  mind  that 
even  a  stout  bar  of  medium  length  will  spring  consider- 
ably from  an  ordinary  roughing-out  cut,  though  the  latter 

Fig.  167. 


be  of  an  equal  depth  all  round  the  bore  and  from  end  to 
end  of  the  work.  Position  No.  3,  in  Fig.  166,  then  is 
decidedly  preferable  for  the  roughiug-out  cuts.  In  the 
finishing  cuts,  which  should  be  very  light  ones,  neither 
the  bar  nor  the  tool  are  so  much  affected  by  springing; 
but  even  here  position  No.  3  maintains  its  superiority, 
because,  the  tool  being  pulled,  it  operates  somewhat  as  a 
scraper  (though  it  may  be  as  keen  in  shape  as  the  other 
tools)  and  hence  it  cuts  more  smoothly. 
16* 


186 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  167  represents  a  boring  bar,  the  cutters  standing  to 
one  side  of  the  bar  axis  so  as  to  carry  out  the  principle 
explained  with  reference  to  figure  166. 

Fig.  168  represents  a  boring  bar  having  three  cutters, 
and  it  will  be  seen  that  if  one  cutter,  as  A,  leaves  its  cut. 
the  pressure  of  the  cut  on  the  other  two  will  spring  the 
bar  towards  A,  and  the  whole  will  not  be  round. 

To  obt  lin  the  very  best  and  most  rapid  result,  them 
should  be  but  little  space  between  the  sliding  head  and 

Fig.  168. 


the  bore  of  the  work ;  the  bar  itself  should  be  as  stout 
as  is  practicable,  leaving  the  sliding  head  of  sufficient 
strength  ;  and  if  the  bar  revolves  in  journals,  these  should 
be  of  large  diameter  and  with  ample  facilities  for  taking 
up  both  the  diametrical  and  end  play  of  the  boxes,  since 
the  one  steadies  the  bar  while  it  is  performing  boring  duty, 
and  the  other  while  it  is  facing  off  end  faces,  as  for  cylin- 
der cover  joints.  The  feed  of  a  boring  bar,  which  is  slight 
in  comparison  to  its  duty,  will  rang,?  at  from  twenty  to 


BORING   BARS.  187 

thirty  revolutions  to  an  inch  of  travel :  while  that  of  a 
stout  bar,  held  in  large  and  closely-fitting  journals,  may 
be  about  sixteen  revolutions  per  inch  of  tool  travel  for 
roughing-out  cuts,  and  four  revolutions  per  inch  of  travel 
for  finishing  cuts,  which  may  be  made  to  leave  the  work 
very  smooth  indeed. 

The  tools  employed  for  the  roughing  cuts  should  not 
have  a  broad  cutting  surface,  and  should  have  a  little 
front  rake.  For  the  finishing  cuts,  the  same  tool  may  be 
employed,  the  end  being  ground  to  have,  for  use  on  cast- 
iron,  a  broad,  level  cutting  surface  along  the  cutting  edge, 
so  that,  while  the  front  edge  of  the  tool  is  cutting,  the 
behind  part  will  scrape  and  thus  smooth  the  cut.  These 
tools  should  be  made  of  the  best  quality  of  steel,  and  hard- 
ened right  out,  that  is  to  say,  not  tempered  at  all. 

The  lip  or  top  rake  must,  in  case  the  bar  should  tremble 
during  the  finishing  cut,  be  ground  off,  leaving  the  face 
level ;  and  if,  from  the  bar  being  too  slight  for  its  duty,  it 
should  still  either  chatter  or  jar,  it  will  pay  best  to  reduce 
the  revolutions  per  minute  of  the  bar,  keeping  the  feed  as 
coarse  as  possible,  which  will  give  the  best  results  in  a 
given  time.  In  cases  where,  frrni  the  excessive  length 
and  smallness  of  the  bar,  it  is  difficult  to  prevent  it  from 
springing,  the  cutters  must  be  made  with  no  lip,  and  but  a 
small  amount  of  cutting  surface;  and  the  corner  A  should 
be  bevelled  off  as  shown.  Under  these  conditions,  the  tool 
is  the  least  likely  to  chatter  or  to  spring  into  the  cut, 
especially  if  held  in  position  No.  3,  in  Fig.  166,  for  a  tool 
which  would  jar  violently  in  position  No.  1  would  cut 
smoothly  and  well  if  held  in  position  No.  3. 

The  shape  of  the  cutting  corner  of  a  cutter  depends 
entirely  upon  the  position  of  its  clearance  or  rake.  If  the 
edge  forming  the  diameter  has  no  clearance  upon  it,  the 
cutting  being  performed  by  the  end  edges,  the  cutter  may 
be  left  with  a  square,  slightly  rounded,  or  bevelled  corner; 
but  if  the  cutter  have  clearance  on  its  outside  or  diamet- 


188  COMPLETE  PRACTICAL  MACHINIST. 

rical  edge,  as  shown  on  the  cutters  in  Fig.  166,  the  cutting 
corner  should  be  bevelled  or  rounded  off,  otherwise  it  will 
jar  in  taking  a  roughing  cut,  and  chatter  in  taking  a 
moderate  cut.  The  principle  is,  that  bevelling  off  the 
front  edge  of  the  cutter  tends  greatly  to  counteract  a  dis- 
position to  either  jarring  or  chattering,  especially  as 
applied  to  brass  work. 

The  only  other  precaution  which  can  be  taken  to  pre- 
vent, in  exceptional  cases,  the  spring  of  a  boring  bar  is  to 
provide  a  bearing  at  each  end  of  the  work,  as,  for  instance, 
by  bolting  to  the  end  of  the  work  four  iron  plates,  the 
ends  being  hollowed  to  fit  the  bar,  and  being  so  adjusted 
as  to  barely  touch  it ;  so  that,  while  the  bar  will  not  be 
sprung  by  the  plates,  yet,  if  it  tends  to  spring  out  of  true, 
it  will  be  prevented  from  doing  so  by  contact  with  the 
hollow  ends  of  the  plates,  which  latter  should  have  a  wide 
bearing  and  be  kept  well  lubricated. 

It  sometimes  happens  that  from  play  in  the  journals  of 
the  machine,  or  from  other  causes,  a  boring  bar  will  jar  or 
chatter  at  the  commencement  of  a  bore,  and  will  gradually 
cease  to  do  so  as  the  cut  proceeds  and  the  cutter  gets  a 
broader  bearing  on  the  work.  Especially  is  this  liable  to 
occur  in  using  cutters  having  no  clearance  on  the  diamet- 
rical edge ;  because,  so  soon  as  such  a  cutter  has  entered 
the  bore  for  a  short  distance,  the  diametrical  edge  (fitting 
closely  to  the  bore)  acts  as  a  guide  to  steady  the  cutter. 
If,  however,  the  cutter  has  such  clearance,  the  only  per- 
ceptible reason  is  that  the  chattering  ceases  as  soon  as  the 
cutting  edge  of  the  tool  or  cutter  has  lost  its  fibrous  edges. 
The  natural  remedy  for  this  would  appear  to  be  to  apply 
the  oil-stone;  this,  however,  will  either  have  no  effect  or 
make  matters  worse.  It  is,  indeed,  a  far  better  plan  to  take 
the  tool  (after  grinding)  and  rub  the  cutting  edge  into  a 
piece  of  soft  wood,  and  to  apply  oil  to  the  tool  during  its  first 
two  or  three  cutting  revolutions.  The  application  of  oil  will 
often  remedy  a  slight  existing  chattering  of  a  boring  bar, 


BORING  BARS. 


189 


but  it  is  an  expedient  to  be  avoided,  if  possible,  since  the 
diameter  or  "bore  cut  with  oil  will  vary  i'rom  that  cut  dry, 
the  latter  being  a  trifle  the  larger. 

The  considerations,  therefore,  which  determine  the  shape 
of  a  cutter  to  he  employed  are  as  follows :  Cutters  for  use 
on  a  certain  and  unvarying  size  of  bore  should  have  no 
clearance  on  the  diametrical  edges,  the  cutting  being  per- 
formed by  the  end  edge  only.  Cutters  intended  to  be 
adjusted  to  suit  bores  of  varying  diameter  should  have 
clearance  on  the  end  and  on  the  diametrical  edges.  For 
use  on  brass  work,  the  cutting  corner  should  be  rounded 
off,  and  there  should  be  no  lip  given  to  the  cutting  edge. 
For  wrought-iron  the  cutter  should  be  lipped,  and  oil  or 
soapy  water  should  be  supplied  to  it  during  the  operation. 
A  slight  lip  should  be  given  to  cutters  for  use  on  cast-iron, 
unless,  from  slightness  in  the  bar  or  other  causes,  there  is 
a  tendency  to  jarring,  in  which  case  no  lip  or  front  rake 
should  be  given. 

SMALL   BORING   BARS. 

In  boring  work  chucked  and  revolved  in  the  lathe,  such, 
for  instance,  r,s  axle  boxes  for  locomotives,  the  device 
shown  in  Fig.  169  is  an  excellent  tool.  A  represents  a 

.  169. 


cutter  head,  which  slides  along,  at  a  close  working  fit,  upon 
the  bar  D  D,  and  is  provided  with  the  cutters  B  B  B, 
which  are  fastened  into  slots  provided  in  the  head  A,  by 


190  COMPLETE  PRACTICAL  MACHINIST. 

the  keys  shown.  The  bar  D  D  has  a  thread  cut  upon  part 
of  its  length,  the  remainder  being  plain,  to  fit  the  sliding 
head.  One  end  is  squared  to  receive  a  wrench,  which, 
resting  against  the  bed  of  the  lathe,  prevents  the  bar  from 
revolving  upon  the  lathe  centres  F  F,  by  which  the  bar  is 
held  in  the  lathe.  G  G  G  are  plain  washers,  provided  to 
make  up  the  distance  between  the  thread  and  plain  part  of 
the  bar,  in  cases  where  the  sliding  head  A  requires  consid- 
erable lateral  movement,  there  being  more  or  fewer  washers 
employed  according  to  the  distance  along  which  the  sliding 
head  is  required  to  move.  The  edges  of  these  washers  are 
chamfered  off  to  prevent  them  from  burring  easily.  To 
feed  the  cutters,  the  nut  H  is  screwed  up  with  a  wrench. 

The  cutter  head  A  is  provided  in  its  bore  with  two 
feathers,  which  slide  in  grooves  provided  in  the  bar  D  D, 
thus  preventing  the  head  from  revolving  upon  the  bar. 
It  is  obvious  that  this  bar  will,  in  consequence  of  its 
rigidity,  take  out  a  much  heavier  cut  than  would  be  pos- 
sible with  any  boring  tool,  and  furthermore  that,  there 
being  four  cutters,  they  can  be  fed  up  four  times  as  fast  as 
would  be  possible  with  a  single  tool  or  cutter.  Care  must, 
however,  be  exercised  to  so  set  the  cutters  that  they  will 
all  project  true  radially,  so  that  the  depth  of  cut  taken  by 
each  will  be  equal,  or  practically  so  ;  otherwise  the  feeding 
cannot  progress  any  faster  than  if  one  cutter  only  were 
employed. 

For  use  on  bores  of  a  standard  size,  the  cutters  may  be 
made  with  a  projecting  feather,  fitting  into  a  groove  pro- 
vided in  the  head  to  receive  them.  The  cutters  should  be 
fitted  to  their  places,  and  each  marked  to  its  place;  so 
that,  if  the  keyways  should  vary  a  little  in  their  radius 
from  the  centre  of  the  bar,  they  will  nevertheless  be  true 
when  in  use,  if  always  placed  in  the  slot  in  which  they 
were  turned  up  when  made.  By  fitting  in  several  sets  of 
cutters  and  turning  them  up  to  standard  sizes,  correctness 
in  the  size  of  bore  may  be  at  all  times  insured,  and  the 
feeding  may  be  performed  very  fast  indeed. 


CHAPTER  X. 

SLOTTING    MACHINE   TOOLS. 

TOOLS  for  use  in  slotting  machines  are  divided  into  two 
classes :  those  used  by  themselves,  for  holes  in  which  there 
is  not  sufficient  room  to  admit  a  tool-post  or  bar  ;  and  short 
tools,  held  in  a  tool-post  on  the  bar,  and  fastened  by  a  set 
screw  or  screws  thereon  provided. 

Referring  to  the  first  class,  it  is  advantageous  to  let  the 
cutting  edge  of  the  tool  stand  below  the  level  of  the 
bottom  of  the  tool  steel,  so  that  in  springing  or  deflecting 
from  the  pressure  of  the  cut,  which  it  is  sure  to  do  in 
some  degree,  the  tool  point  will  enter  deeper  into  its  cut, 
and  will  not,  therefore,  rub  against  it  during  the  back  or 
return  stroke  of  the  tool,  as  it  is  apt  to  do  if  the  tool  edge 
is  level  with  the  bottom  of  the  tool  steel. 

If  the  tool  edge  is  level  with  the  middle  of  the  tool 
steel,  the  spring  or  deflection,  due  to  the  strain  or  pressure 
of  the  cut,  causes  the  cutting  edge  to  spring  away  from 
the  work,  and,  therefore,  lessen  the  depth  of  the  cut ; 
hence  during  the  back  stroke  the  tool,  being  relieved  of 
strain,  rubs  against  the  side  of  the  cut,  aud  the  abrasion 
rapidly  dulls  the  cutting  edge.  Similarly  by  giving  the 
front  face  side  rake,  the  tool  will  move  slightly  in  the 
direction  of  the  feed  during  the  cutting  stroke,  and  be 
correspondingly  relieved  during  its  return  stroke.  When 
the  tool  is  slight  and  stands  far  out  from  the  slide  or  ram 
of  the  machine,  it  will  spring  enough  to  make  the  work  a 
straight  taper ;  hence  key  ways  cut  in  small  bores  will  get 
some  of  their  taper  from  this  spring. 

(191) 


COMPLETE  PRACTICAL  MACHINIST. 


For  cutting  out  a  half  round  groove,  the  tool  shown  in 
Fig.  170rfhould  be  employed.  The  outline  A  is  made  as 
denoted  by  the  dotted  line  B  in  cases  where,  from  the 
narrowness  of  the  tool,  it  is  very  liable  to  spring  from  the 
pressure  of  the  cut,  as, 
say,  when  the  thickness,  at  Fl9'  170< 

C  is  less  than  three-eighths 
inch,  in  which  case  the 
cutting  edge  should  be 
lowered  to  a  straw  color ; 
whereas,  if  thicker,  the 
edge  may  be  hardened 
right  out.  It  is  well  here 
to  note  that  ifc  is  advan- 
tageous that  the  tool 
should  have  a  barely  per- 
ceptible amount  of  spring, 
in  the  direction  of  its 
cut,  because  otherwise  the 
edge  of  the  tool  will  rub 
against  the  work  during 
the  back  stroke,  and  thus 
become  rapidly  dulled. 

Whenever  the  nature  of  the  work  to  be  done  will  admit, 
a  holding  bar  and  short  tool,  such  as  shown  in  Fig.  171  may 
be  used. 

By  using  such  a  bar,  short  tools,  such  as  have  been 
already  described  for  use  in  the  lathe  or  planer,  may  be 
employed,  their  shortness  rendering  their  grinding  and 
forging  much  easier  of  accomplishment.  Many  of  these 
holding  bars  have  small  pivoted  boxes,  similar  to  that 
shown  in  Fig.  171,  provided  to  receive  the  tool.  A  is  a 
sectional  view  of  the  bar,  B  is  the  box,  pivoted  at  C,  D  is 
the  tool,  and  E  the  set  screw  for  holding  the  same.  It 
will  be  observed  that  the  set  screw  E  screws  into  the 
pivoted  box,  and  not  into  the  end  of  the  bar,  and  that  the 


LJ 


SLOTTING   TOOLS. 


193 


hole,  provided  in  the  end  of  the- bar 'to  admit  the  set 
screw,  is  large  enough  to  permit  the  set  screw  to  have 
plenty  of  play  or  movement.  The  object  of  this  and  simi- 
larly designed  devices  is  to  allow  the  tool  to  move,  in  the 
direction  of  D,  off  the  pivot  C,  and  thus  to  prevent  the 
tool  edge  from  rubbing  against  the  sides  of  its  cut  during 
the  up  stroke  of  the  bar,  the  spiral  spring  shown  being 
made  sufficiently  strong  to  support  the  box  B  in  the 
position  shown,  but  not  sufficiently  strong  to  resist  much 
force  exerted  upon  the  tool  and  in  the  direction  of  D. 
For  small  or  even  medium  sized  work  these  devices  are 


Fig.  171. 


^- 

\ 


very  efficient ;  but  for  large,  heavy,  outside  work,  the  ban 
themselves  are  too  slight,  and  it  is  usual  to  employ  a 
similar  device  (on  a  large  scale)  provided  in  the  tool  end 
of  the  slide  itself.  Under  these  conditions  the  slotting 
machine  will  perform  as  heavy  duty  as  either  the  lathe  or 
planing  machine.  The  writer  has  in  his  possession  a  cut- 
ting taken  off  the  outside  of  a  crank  at  the  Morgan  Iron 
Works,  which  cutting  was  taken  at  a  cut  2|  inches  deep,  and 
is  a  full  |  of  an  inch  in  thickness,  the  tool  employed  being 
17 


194 


COMPLETE  PRACTICAL  MACHINIST. 


a  knife  tool,  ground  as  shown  in  Fig.  172.  B  represents 
the  tool  end  of  the  slide  of  the  slotting  machine,  A  the 
knife  tool,  C  the  work,  and  from  D  to  JE  the  depth  of 
the  cut. 

The  face  of  the  tool  is  ground  off  at  an  angle,  in  the 
direction  of  I,  so  that  the  point  of  the  tool  shall  not  break 
off  when  it  strikes  the  work,  and  so  that  the  strain  upon 
the  tool  and  working  parts  of  the  machine  shall  not  come 
upon  them  too  suddenly,  and  cause  them  to  break,  as 
would  be  the  case  were  the  cutting  edge  of  the  tool  te 
strike  the  cut  along  its  whole  length  simultaneously.  As 


Fig.  172. 


shown  in  the  engraving,  the  tool  would  strike  the  work  at 
F  on  the  edge  only,  which  would  for  an  instant  of  time 
exert  only  enough  resistance  to  bring  all  the  working 
parts  of  the  machine  to  a  bearing;  and  as  the  tool  de- 
scended, the  strain  would  gradually  increase  until  the 
point  of  the  tool  reached  the  work.  When  the  tool  is  near 
the  end  of  the  stroke,  and  therefore  leaves  the  cut,  it  will 
do  so  at  F  first,  thus  leaving  the  cut  gradually,  and  greatly 
modifying  the  jump  due  to  the  recoil  of  the  working  parts 
of  the  machine  when  relieved  of  the  heavy  strain  necessary 
to  drive  such  a  deep  and  thick  cut.  The  enormous  strain 


SLOTTING   TOOLS.  195 

placed  upon  the  tool  would  inevitably  break  it  were  it  left 
very  hard ;  it  is  therefore  tempered  to  a  purple. 

No  other  tool  can  well  be  used  for  taking  such  heavy 
cuts,  because  grinding  off  the  face,  F,  of  any  other  tool 
would  not  leave  the  tool  edge  sufficiently  keen  to  sever  the 
metal  without  an  excessive  amount  of  driving  power;  and 
further,  because  the  breadth  of  the  face  F,  which  sustains 
the  force  necessary  to  bend  the  cutting,  is  narrower  in  the 
kiiife  tool  than  in  any  other,  and  therefore  bends  the  cut- 
ting less,  experiencing  a  corresponding  decrease  of  strain. 
Cuts  of  such  great  depth  and  thickness  cannot  be  well 
taken  in  slotting  machines  whose  slides  are  operated  by  a 
connecting  rod  or  link,  because  the  excessive  strain  would 
be  apt  to  force  the  connecting  rod  along  the  slot  provided 
to  alter  the  stroke  of  the  machine;  the  eliding  head  is 
therefore  provided  with  a  strong  rack  on  each  side,  oper- 
ated by  pinions,  with  suitable  reversing  gearing  attached 
for  varying  the  stroke. 

When  operating  the  feed  of  a  slotting  machine  by  hand, 
the  work  should  be  fed  to  the  cut  while  the  tool  is  revers- 
ing its  motion  at  the  top  of  the  stroke,  and  not  while  the 
tool  is  cutting  or  at  the  bottom  of  the  stroke,  because,  in 
either  of  the  latter  cases,  the  tool  edge  would  grind  against 
the  sides  of  the  cut  during  the  up  stroke,  which  would  soon 
impair  the  cutting  qualifications  of  the  tool. 

Tool-holding  bars  of  sizes  below  about  1|  inches  in 
thickness  should  be  made  of  steel  so  as  to  be  strong 
enough  to  resist  the  tendency  to  spring.  For  sizes  above 
that  they  may  be  made  of  wrought-irou. 


CHAPTER    XI. 

TWIST    DRILLS. 

TWMST  drills  are  not,  as  is  usually  supposed,  of 
the  same  diameter  from  end  to  end  of  the  twist, 
but  are  slightly  taper,  diminishing  towards  the 
shank  end.  The  taper  is  usually,  however,  so 
slight  as  to  be  of  little  consequence  in  actual  prac- 
tice. Neither  are  twist  drills  round,  the  diameter 
being  eased  away  from  a  short  distance  behind  the 
advance  or  cutting  edge  of  the  flute,  backward  to 
the  next  flute,  so  as  to  reduce  the  friction  of  the  sides 
of  the  drill  upon  the  hole  and  give  the  sides  of  the 
drill  as  much  clearance  as  possible.  The  advance 
edges  of  the  flutes  are  left  of  a  full  circle,  which 
maintains  the  diameter  of  the  drill  and  steadies 
it  in  the  hole.  If,  from  excessive  duty,  that  part 
left  a  full  circle  should  wear  away  at  the  cutting 
end  of  the  drill,  leaving  the  corner  of  the  drill 
rounded,  the  drill  must  be  ground  sufficiently  to 
cut  away  entirely  the  worn  part,  otherwise  it  will 
totally  impair  the  value  of  the  drill,  causing  it  to  ; 
grind  against  the  metal,  and  no  amount  of  pres- 
sure will  cause  it  to  cut.  The  advantage  over 
other  drills  possessed  by  the  twist  drill  is  that 
the  cuttings  can  find  free  egress,  which  effects 
a  gre^it  saving  of  time,  for  plain  drills  have 
to  be  frequently  withdrawn  from  the  'hole  to 
extract  the  cuttings,  which  would  jamb  between 
the  sides  of  the  hole  and  the  sides  of  the  drill, 
and  the  pressure  will  frequently  become  so  great  as  to 
cwist  or  break  the  shank  of  the  drill,  especially  in  small 
196 


TWIST  DRILLS. 


197 


holes.  In  point  of  fact,  the  advent  of  twist  drills  has 
rendered  the  employment  of  the  flat  drill  for  use  in  small 
holes  (that  is  to  say,  from  t  inch  downwards)  totally 
inexcusable,  except  it  be  for  metal  so  hard  as  to  require 
a  drill  tempered  to  suit  the  work.  Other  advantages 
of  the  twist  drill  are,  that  it 
always  runs  true,  requires 
no  reforging  or  tempering, 
and,  by  reason  of  its  shape, 
fits  closely  to  the  hole,  and 
hence  drills  a  straight  and 
parallel  hole,  providing  it  is 
ground  true. 

The  cutting  edges  are 
usualTy  ground  to  an  angle 
of  60  degrees  to  the  centre 
line  of  the  drill,  as  shown  in 
Fig.  177,  but  will  be  found 
to  work  more  satisfactorily 
if  ground  to  an  angle  of  50 
degrees  when  used  on  brass 
work. 

The  line  shown  along  the 
centre  of  the  flutes,  in  Fig. 
173,  is  to  serve  as  a  guide  in 
grinding  the  point  central 
when  the  drill  is  ground  by 
hand,  but  more  duty  and  more 
accurate  work  may  be  ob- 
tained if  the  drill  is  ground 
in  a  twist  drill  grinding 
machine,  so  that  the  cutting  edges  may  be  ground  true, 
and  both  cutting  edges  may  perform  equal  duty. 

In  Fig.  174  is  shown  a  twist  drill,  having  an  edge  e 
ground  longer  than  the  other,  and  the  effect  of  this  is  that 
if  the  drill  feed  is  T-J<y  inch  per  revolution,  the  whole  of 
17* 


198 


COMPLETE  PRACTICAL  MACHINIST. 


this 'feed  will  fall  on  edge  e,  and  being  double  what  it 
should  be  would  cause  that  edge  to  dull  more  rapidly 
than  it  should  do.  Again,  the  drill'  would  produce 
a  hole  of  larger  diameter  than  itself,  because  the  point 


Fig.  175. 


of  the  drill  would  be  forced  by  the  feed  to  become  the 
axis  of  revolution,  which  would,  therefore,  be  on  the 
line  b  b. 

In  Fig.  175  is  shown  a  twist  drill  in  which  one  cutting 
edge  is  longer  than  the  other,  and  the  two  cutting  edges 
are  not  at  the  same  angle  to  the  drill  axis  a  a.  Here 


TWIST  DRILLS. 


199 


again  the  axis  of  drill  revolution  will  be  on  the  line  b  b 
as  before,  but  both  cutting  edges  will  perform  duty. 
Thus  edge  e'will  pierce  .a  hole  which  the  outer  end  or 
corner  of/  will  enlarge.  Fig.  176  shows  a  case  in  which 
the  point  of  the  drill  is  central  to  its  axis  a  a,  but  the 


Fig.  111. 


178. 


cutting  edges  are  not  at  the  same  angle,  and  as  a  result 
all  the  duty  falls  on  one  cutting  edge,  and  the  hole  drilled 
will  be  larger  in  diameter  than  the  drill  is,  because  there 
is  a  tendency  for  the  cutting  edge  e  to  push  or  crowd  the 
drill  over  to  the  opposite  side  of  the  hole.  Drills  to  be 
ground  by  hand  may  be  tested  for  angle  in  several  ways. 
Thus,  Fig.  177  represents  a  drill  being  tested  by  a  pro-  ^^f 


200 


COMPLETE  PRACTICAL  MACHINIST. 


tractor.  Another  method  is  to  rest  the  drill  upon  a  plate 
and  apply  a  measuring  rule,  as  in  Fig.  178.  Either  of 
these  methods  forms  a  guide  for  testing  the  length  of  the 


cutting  edges,  but  they  are  difficult  of  application  for  very 
small  drills,  and  furthermore  form  no  guide  in  grinding 
the  clearance.  This,  however,  may  be  judged  by  the  ap- 

Fig.  180. 


pearance  of  the  cutting  edge  at  that  point.  Thus,  if  this 
edge  is  at  a  right  angle  to  the  cutting  edges,  as  at  A,  in 
Fig.  179,  there  is  no  clearance ;  while,  in  proportion  as 
clearance  is  given,  this  line  inclines  as  shown  at  B  in  the 


FLAT  DRILLS. 


201 


figure  ;  at  C  an  excessive  amount  of  clearance  is  shown  by 
the  extreme  angle,  while  at  D  the  heels  e  and  /are  shown 
to  stand  higher  than  the  cutting  edges,  because  the  end 
faces  are  ground  at  an  angle  in  the  wrong  direction. 

Fig.  180  represents  the  flat  drill,  whose  defects  are  as 
follows :  First,  when  the  drill  operates  vertically,  as  in 
the  drilling  machine,  the  drill  must  be  removed  to  extract 
the  cuttings  in  all  cases  in  which  the  depth  of  the  drilled 
hole  is  more  than  about  equal  to  its  diameter,  and  this 
occupies  in  deep  holes  more  time  than  the  actual  cutting 
operation.  Secondly,  the  drill  must  be  forged  occasionally 
in  order  to  keep  it  up  to  the  required  size  and  keep  its 

Fig.  181. 


point  thin  enough  for  effective  duty.  Third,  on  account 
of  this  forging  it  is  difficult  to  get  the  drill  to  run  quite 
true,  and  unless  this  is  the  case  the  drill,  when  not  con- 
trolled by  the  hole  in  the  work,  will  revolve  eccentrically; 
but  so  soon  as  the  drill  is  subjected  to  end  pressure  on  the 
work  it  will  endeavor  to  revolve  on  its  point  as  a  centre 
of  revolution,  thus  endeavoring  to  force  the  journal  of 


202 


COMPLETE  PRACTICAL  MACHINIST. 


the  drill  spindle  to  revolve  eccentrically,  subjecting  it  to 
undue  wear  and  involving  the  loss  of  a  large  percentage 
of  the  driving  power  of  the  machine.  Fourth,  the  diam- 
eter of  the  drill  is  dependent  upon  the  workman's  ac- 
curacy in  grinding  it.  Fifth,  the  sides  of  the  drill  form 
but  a  very  indifferent  guide. 

The  keenness  of  a  flat  drill  may  be  increased  by  grind- 
ing a  lip  to  it,  as  at  A,  in  Fig.  181,  but  a  better  method 
is  to  bend  the  lip  forward  when  forging  it,  forming  what 
is  known  as  the  lip  drill  This  greatly  increases  the 

Fig.  182. 


capacity  of  the  drill  for  iron  or  copper,  but  causes  it  to 
rip  and  tear  if  used  upon  brass  work. 

Fig.  182  represents  the  tit  drill,  which  is  employed  to 
flatten  the  bottoms  of  holes.  Its  tit  T  should  be  thinned 
at  the  point,  as  shown,  and  the  side  edges  B  should  have 
little  or  no  clearance  and  left  so  that  its  edges  will  not 
cut. 

FEEDING    DRILLS. 

Much  more  duty  may  be  obtained  from  a  drill  by  feeding 


TWIST  DRILLS.  203 

it  by  hand  than  by  permitting  the  gearing  of  the  machine 
to  feed  it,  because  in  hand  feeding,  the  sense  of  feeling 
indicates  to  the  operator  how  much  cut  the  drill  is  capable 
of  standing,  and  he  can  therefore  vary  the  rate  of  feed, 
keeping  it  up  to  the  maximum  obtainable  on  the  degree 
of  hardness  of  the  metal  being  drilled.  Dullness  of  the 
cutting  edges,  hard  or  soft  spots  in  the  metal,  or  any  other 
variation  in  the  condition  of  the  drill  or  in  the  metal  being 
drilled,  is  at  once  perceived  by  hand  feeding.  Drilling 
machines  have,  it  is  true,  several  degrees  of  feed,  but  the 
fact  is  that  the  human  hand  can  feed  the  drill  at  any  rate 
that  can  be  obtained  by  means  of  machine  gearing ;  and 
having  behind  it  the  human  mind,  it  is  enabled  to  accom- 
modate itself  to  the  numerous  and  variable  conditions 
against  which  no  provision  can  be  made  in  automatic 
feed  gearing.  No  positive  rate  of  feed,  either  for  any 
size  of  drill,  or  for  any  particular  kind  of  metal,  can  be 
given,  because  of  the  always  present  variations  in  the 
degree  of  hardness  of  the  metal  to  be  cut,  and  furthermore 
because,  in  the  case  of  iron  and  steel,  the  facility  of  supply- 
ing the  cutting  edges  with  oil  seriously  affects  the  attain- 
able rate  of  feed  to  the  drill.  If,  for  instance,  the  hole  is 
being  drilled  horizontally,  as  in  a  lathe,  and  is  very  deep, 
so  that  it  is  difficult  to  freely  supply  the  cutting  end  of  the 
drill  with  oil,  the  feeding  must  proceed  slowly  or  the  cut- 
ting edges  of  the  drill  will  soon  become  destroyed  Here, 
also,  it  may  be  well  to  state  that,  if  oil  be  supplied  to  a 
drill  cutting  cast-iron  or  brass,  it  will  cause  the  cuttings  to 
jamb  between  the  sides  of  the  drill  and  the  sides  of  the 
hole,  until  the  pressure  becomes  so  great  as  to  either  stop 
the  drilling  machine  or  lathe,  or  else  twist  or  break  the 
drill.  The  rate  of  feed,  and  the  speed  at  which  the  drill 
should  revolve,  depend  upon  the  hardness  of  the  metal 
under  operation,  although  not  to  a  very  great  extent, 
except  in  the  event  of  the  metal  being  unusually  hard,  in 
which  case  the  drill  should  revolve  very  slowly  ;  for  not 


204  COMPLETE  PRACTICAL  MACHINIST. 

much  latitude  in  the  degree  of  hardness  of  the  drill  is  per- 
missible, for  fear  of  impairing  the  strength  of  the  drill. 

The  temper  for  a  very  small  flat  drill  should  not  be 
higher  than  a  reddish  purple,  but  for  drills  alone  about 
i  inch,  a  coffee  brown  color  will  be  found  preferable.     A 
drilTmay  be  enabled  to  bite  very  hard  metal  by  jagging 
the  metal  surface  with  cold  chisel   marks  and 
rig.  1^83.  forcjng  tne  drill  heavily  to  its  cut,  using  neither 
oil  or  water,  which  would  prevent  the  edges  from 
gripping  the  metal. 

Fig.  183  represents  the  Farmer  lathe  drill, 
having  a  straight  instead  of  a  spiral  flute.  This 
drill  is  accurately  ground  to  size,  and  is  given 
clearance  the  same  as  the  twist  drill,  but  the 
flutes  are  made  straight  along  the  drill  instead 
of  being  spiral.  By  this  means  a  keen  cutting 
edge  and  free  cutting  are  secured  without  the 
tendency  to  run  forward  when  emerging  through 
the  hole,  which  proves  so  destructive  to  twist 
drills,  and  which  is  avoided.  This  is  an  impor- 
tant advantage  upon  thin  work  and  also  upon 
all  brass  work. 

The  shanks  of  machine-made  drills  are  made 
parallel  in  the  small  and  taper  in  the  larger  sizes, 
the  degree  of  taper  being  §  inch  per  foot  of 
length.  Both  the  twist  and  the  straight  flute 
drill  require  to  run  at  a  much  faster  speed  than 
the  flat  drill. 

From  some  experiments  made  by  William 
Sellers  &  Co.,  of  Philadelphia,  it  has  been  found 
that  a  flat  drill  having  one  cutting  edge  at  an 
angle  of  more  than  104  degrees  to  the  other  will  not  move 
its  position  from  the  action  of  the  drawing  chisel. 

The  thinner  the  point  of  a  drill,  the  easier  it  enters  the 
metal  and  is  fed  to  its  cut,  the  limit  of  thinness  being  that 
which  will  leave  sufficient  strength  to  avoid  breakage. 


DRILLING  HARD  METALS.  205 

The  angle  at  which  to  grind  the  end  of  the  drill  is 
governed  to  a  large  extent  by  the  kind  and  degree  of  hard- 
ness of  the  metal  to  be  drilled. 

DRILLING    HARD    METALS. 

Very  hard  metal,  such  as  steel  tempered  to  a  blue,  may  be 
drilled  by  a  drill  tempered  to  a  deep  straw  color,  the  drill 
being  used  at  a  comparatively  slow  speed,  and  forced  against 
the  work  as  Irard  as  possible  without  breaking  the  point  of 
the  drill.  Sufficient  oil  may  be  applied,  after  the  point  of 
the  drill  has  entered  the  metal,  to  keep  the  cutting  edges 
barely  moist,  the  drill  being  again  allowed  to  run  dry  and 
again  moistened,  thus  using  as  small  an  amount  of  oil  as 
is  consistent  with  keeping  the  drill  cool.  In  this  way  the 
drill  will  cut  hard  steel  the  best.  For  cast-iron,  however, 
the  drill  should  be  kept  as  dry  as  possible.  In  drilling 
casf-'ron  that  is  very  hard,  and  also  wrought-iron  that  has 
been  case-hardened,  the  operation  maybe  greatly  assisted 
by  taking  a  hammer  and  a  chisel,  and  jagging  the  surface 
of  the  metal,  thus  enabling  the  edges  of  the  drill  to  bite  it. 

If  necessary,  the  chisel  may  be  made  very  hard  for  this 
especial  purpose. 

To  make  a  drill  exceedingly  hard  to  suit  some  especial 
case,  it  maybe  heated  in  a  charcoal  firo  to  a  dull  red  heat, 
and  quenched  in  mercury  instead  of  water.  Another 
method  is  to  heat  the  drill  to  a  red  heat  in  molten  lead, 
and  then  to  drive  it  into  a  block  of  cold  lead,  striking 
successive  blows  lightly  and  quickly  until  the  drill  is  suf- 
ficiently cool  to  permit  of  its  being  held  in  the  hand.  The 
cases,  however,  in  which  a  drill  is  required  to  be  so  hard 
are  exceedingly  rare. 

If  a  drill  squeaks  while  being  operated,  it  arises  from 
one  of  two  causes :  either  the  cutting  edges  are  dull,  and 
require  grinding,  or  else  the  cuttings  are  binding  in  the 
holes.  In  the  first  case,  immediate  grinding  is  necessary; 
in  the  second,  the  drill  should  be  withdrawn  and  the  cut- 
18 


206 


COMPLETE  PRACTICAL  MACHINIST. 


tings  extracted.  Twist  drills  will  bring  out  most  of  the 
cuttings  of  themselves,  but  a  piece  of  wire,  spoon-shaped 
at  the  ond,  is  necessary  when  plain  drills  are  used» 

SLOTTING   OR    KEYWAY    DRILLS. 

For  drilling  out  oblong  holes,  such  as  key  ways,  or  for 
cutting  out  recesses  such  as  are  required  to  receive  short 
feathers  in  shafts,  the  drill  known  as  a  slotting  drill,  shown 
in  Fig.l84,is  brought  into  requisition.  No.  1  is  the  form 


Fig.  184. ' 


No.  1. 


No.  2. 

in  which  this  tool  was  employed  in  the  early  days  of  its 
introduction  ;  it  is  the  stronger  form  of  the  two,  and  will 
take  the  heaviest  cut.  The  objection  to  it,  however,  is 


KEYWAY  DRILLS. 


207 


that,  in  cutting  out  deep  slots,  it  is  apt  to  drill  out  of  true, 
the  hole  gradually  running  to  one  side.  Suppose,  for 
instance,  as  is  sometimes  the  case,  the  slot  or  key  way  is  so 
deep  that  it  becomes  desirable  to  avoid  having  an  extra 
long  drill,  which  would  be  liable  to  bend  and  spring  from 
the  pressure  of  the  cut,  and  hence  that  a  shorter  drill  is 
used,  drilling  the  key  way  half  way  from  each  side ;  the 
tendency  of  such  a  drill  would  be  to  run  to  one  side,  so 
that  the  junction  of  the  halves  drilled  from  each  side  will 
not  come  fair. 

The  drill  having  entered  on  one  side,  and  then  on  the 
other  side,  and  having  cut  down  until  it  arrived  at  the 
centre,  and  hence  cut  the  keyway  clear  through  the  metal, 
ti nd  the  junction  of  the  two  not  being  even  at  centre,  it 
is  evident  that  the  keyway  will  require  considerable  filing 
to  make  the  faces  so  true,  level,  and  parallel  that  the  key 
will  fit  all  the  way  through.  To  remedy  this  defect,  the  form 
of  drill  shown  in  No.  2  has  been  brought  into  use.  It  will 
be  observed  that  it  enters  the  metal  at  the  points  A  A  first, 
and  therefore  cuts  a  ring  of  metal  out,  leaving  a  projecting 
piece  in  the  centre  which  serves  as  a  guide  to  steady  it ; 
whereas  form  No.  1  cuts  a  flat-bottomed  hole.  So  that,  if 
both  drills  were  simply  rotated  and  fed  as  a  common  drill, 
the  holes  made  by  them  would  appear  as  in  Fig.  185.  It 

Fig.  185. 


will  be  observed  that  in  No.  1  the  bevelled   corners  A 
aione  steady  the  drill,  while  in  No.  2  there  is  the  whole 


208  COMPLETE  PRACTICAL  MACHINIST. 

core  A  tending  to  steady  it,  in  addition  to  the  round 
corners  B  B.  In  practice,  however,  only  the  round  cor- 
ners act  to  steady  it,  because  of  the  light  depth  of  the  cut. 
These  drills,  are,  however,  never  used  to  bore  round  holes, 
but  oblong  ones  only,  which  is  accomplished  by  either 
causing  the  drill  to  travel  back  and  forth  to  the  required 
length  of  the  hole,  the  work  being  held  stationary,  or  else 
by  revolving  the  drill  in  a  stationary  position,  while  the 
table  to  which  the  work  is  bolted  travels  back  and  forth 
to  the  requisite  distance,  the  cut  in  either  case  being  fed  to 
the  drill  at  each  end  of  the  travel.  Thus  a  slot  equal  to 
the  length  of  the  travel  of  the  work  or  the  drill,  as  the 
case  may  be,  and  of  a  width  equal  to  the  diameter  of  the 
drill,  is  made.  If  drill  No.  1  is  employed  to  cut  a  recess, 
it  will  leave  an  angular  corner,  while  No.  2  will  of  course 
leave  a  round  one,  the  bottom  of  the  recess  in  either  case 
being  left  quite  flat,  since  the  bottom  of  No.  1  is  flat  of 
itself,  while  the  rounded  corner  of  No.  2  cuts  away  as  it 
travels  along,  the  cone  A,  which,  as  shown  in  Fig.  185,is 
made  when  neither  the  drill  nor  the  work  travels. 

Slot  drill  No.  1  is  made  by  filing  the  cutting  end  square, 
level  and  true  to  the  requisite  diameter  and  shape,  and 
then  backing  off,  that  is  filing  away  on  one  side,  the  edges 
from  the  centre  of  the  drill,  outwards  and  across  the 
bevelled  corner,  as  shown  in  Fig.  184;  while  No.  2  is  made 
by  filing  up  the  cutting  end  true,  level,  and  square,  and 
then  filing  out  the  curved  hollow  centrally  in  the  end  face, 
with  a  round  file  held  at  an  angle  with  the  centre  line  or* 
the  width  of  the  drill,  as  shown  by  the  dotted  line  C,  in 
the  end  view  of  No.  2  in  Fig.l84,after  which  the  corners 
A  A  should  be  rounded  and  backed  off.  The  thickness  at 
the  cutting  end  of  drill  No.  1  should  be  the  same  as  that 
given  for  common  drills,  while  No.  2  maybe  left  somewhat 
thicker,  to  give  it  extra  strength,  since  its  form  renders  it 
comparatively  weak.  The  reason  for  keeping  the  end  of 
No.  1  as  thin  as  a  common  drill  is,  that  it  has,  at  the  June- 


KEY  WAY  DRILLS.  209 

tion  of  its  two  cutting  edges,  centrally  on  the  end  face  and 
between  the  bevelled  corners,  a  cutting  edge  across  the 
thickness  of  the  drill,  as  shown  in  end  view,  Fig.  184, and 
is  in  that  respect  subject  to  the  defect  before  mentioned  as 
inherent  in  common  drills.  This  defect  does  not,  however, 
exist  in  slotting  drill  No.  2,  in  which  the  cutting  edges  on 
the  outside  faces  extend  clear  to  the  centre  of  the  diameter 
of  the  drill. 

Slotting  drill?  should  be  tempered  to  a  deep  brown,  and 
should  be  supplied  freely  with  oil  when  employed  to  cut 
wrought-iron  or  steel,  but  must  be  kept  perfectly  dry  when 
used  upon  cast-iron  or  brass.  They  are  revolved  at  a 
higher  rate  of  speed  than  common  drills.  To  employ  them 
in  a  common  drilling  machine  whose  table  has  no  horizon- 
tal sliding  motion,  it  is  necessary  to  make  a  chuck  which 
will  bolt  to  the  machine  table;  the  chuck  is  to  be  provided 
with  a  pair  of  jaws  to  clamp  the  work,  and  to  make  the 
upper  part  of  the  chuck  movable  upon  a  slide  in  the  lower 
part. 

In  using  such  a  chuck,  the  operator  will  be  very  apt  to 
vary  the  distance  to  which  he  moves  the  slide  at  each  cut, 
the  effect  of  such  variation  being  to  cause  the  edge  of  the 
slot  or  key  way  to  be  very  uneven.  To  remedy  this,  it  is 
best,  after  having  drilled  to  the  proper  depth,  to  wind  the 
slide  and  set  the  drill  so  that  it  takes  a  slight  cut  out  of 
one  end  of  the  slot  at  the  top,  and  then  (keeping  the 
chuck  stationary)  to  feed  the  drill  down  through  the  slot, 
thus  cutting  the  end  out  quite  even.  In  taking  the  first 
few  cuts  at  the  commencement  of  the  operation,  that  is  to 
say,  immediately  after  the  work  is  chucked,  it  is  better  to 
cut  the  slot  a  little  less  than  the  required  breadth,  so  as  to 
leave  a  little  to  come  out  of  each  end  of  the  slot  (as  above 
described)  to  true  it.  It  is  obvious  that  parallel  strips 
may  be  employed  in  the  jaws,  whereon  to  rest  the  work,  or 
to  make  up  the  width  between  the  ends  of  the  screws,  and 
the  opposite  jaw  of  the  chuck,, 
18 


210  COMPLETE  PRACTICAL  MACHINIST. 

There  is  probably  no  one  cutting  tool  used  in  a  machine 
which  saves  so  much  labor  as  the  slotting  drill,  because  it 
performs  a  duty  that  no  other  tool  or  machine  can  per- 
form, and  which  is  moreover  a  most  difficult  and  tedious 
one.  Before  the  advent  of  this  tool,  deep  keyways  were 
cut  out  of  the  solid  metal  in  the  following  manner :  first, 
plain  holes  were  drilled  through  the  work,  then  these  holes 
were  plugged  up  by  having  pieces  of  round  iron  driven 
tightly  in  them.  Then  new  holes  were  drilled,  the  centre 
of  each  new  hole  being  in  the  thin  wall  of  solid  metal 
between  the  plugged  holes.  AAer  the  latter  holes  were 
drilled,  the  remains  of  the  plugs  were  driven  out,  the  sides 
of  the  keyway  would  present  a  serrated  appearance.  This 
entailed  an  almost  incredible  amount  of  chipping  and 
filing  in  order  to  make  the  sides  of  the  keyway  level  and 
true,  and  the  width  parallel.  This  method  of  procedure  is, 
however,  still  in  vogue  to  a  slight  extent,  being  confined 
mainly  to  jobbing  and  repair  shops.  It  is  also  employed 
for  very  narrow  and  deep  holes,  since  a  slotting  drill  can- 
not be  employed  to  advantage  in  holes  of  less  than  about 
i5g  of  an  inch  in  diameter,  because  of  the  bending  and 
springing  of  the  drill.  If,  however,  twist  drills  are  em- 
ployed to  drill  the  small  holes,  the  plugging  with  pieces 
of  iron  may  bs  dispensed  with,  since  the  holes  may  be 
drilled  so  as  to  run  one  into  the  other ;  in  this  case  every 
other  hole  should  be  drilled  first,  and  then  in  drilling  the 
intermediate  holes  the  drill  will  not  run  to  one  side  or  the 
other. 

It  may  here  be  observed  that  the  principles  of  the  action 
of  the  slot  drill  have  been  applied  to  a  variety  of  purposes 
in  woodworking,  prominent  among  which  is  its  use  in 
Boult's  panelling  and  dovetailing  machine.  In  its  adapta- 
tion to  wood,  as  in  its  adaptation  to  iron,  there  is  no  othei 
tool  at  all  capable  of  performing  the  same  kind  of  duty, 
irrespective  of  either  time  or  quality. 

Keyways  or  slots  that  are  wide  enough  to  admit  a  stout 


PIN  DRILLS. 


211 


tool  may  be  cut  by  drilling  a  hole  the  width  of  the  re- 
quired keyway  at  one  end,  and  then  cutting  out  the  re- 
mainder of  the  keyway  in  the  slotting  machine.  All 
ordinary  keyways,  however,  are  cut  quicker  and  better 
with  the  slot  drill. 

PIN    DRILLS. 

'  The  next  form  in  which  the  drill  appears  is  the  pin  drill, 
which  is  a  drill  having  a  pin  projecting  beyond  and  between 
its  cutting  edges,  as  shown  in  Fig.  186,  A  A  being  the  cut- 

J%.186. 


ting  edges.  The  purpose  of  this  drill  is  to  face  off  the 
metal  round  the  outside  of  holes,  the  pin  B  fitting  into 
the  hole  so  as  to  steady  the  drill  and  keep  it  true  with  the 
bole.  In  making  this  tool,  the  pin  B,  the  edges  C,  and 
the  ends  forming  the  cutting  edges  A  A,  should  be  turned 
up  true  in  the  lathe ;  the  backing  off  may  then  be  filed, 
leaving  the  cutting  edges  A  with  the  turning  marks  barely 
effaced  ;  thus  they  will  be  sure  to  be  true  and  at  an  equal 
height  from  the  end  of  the  pin,  so  that  both  the  cutting 


212 


COMPLETE  PRACTICAL  MACHINIST. 


edges  will  perform  duty,  and  not  one  only,  as  would  be 
otherwise  the  case.  Pin  drills  should  be  tempered  to  a 
deep  straw  color,  and  run  at  a  comparatively  slow  speed, 
using  oil  for  wrought-iron  and  steel,  and  running  dry  on 
cast-iron  and  brass.  In  cases  where,  for  want  of  an  assort- 
ment of  pin  drills,  there  is  none  at  hand  with  a  pin  suitable 
for  the  size  of  hole  required  to  be  faced,  a  drill  having  one 
too  small  for  the  hole  may  be  made  up  to  the  required  size 
by  placing  upon  it  a  ring  of  iron  or  brass  of  the  requisite 
thickness  and  about  equal  in  depth  to  the  pin. 

COUNTERSINK    DRILLS. 

Of  countersinks,  there  are  various  forms  ;  but  before  pro- 
ceeding to  describe  them,  it  may  be  as  well  to  observe  that 
the  pin  drill  described  above  may  be  employed  as  a  flat- 
bottomed  countersink.  Fig.  187  represents  a  taper  countcr- 

Fig.  187. 


sink,  such  as  is  employed  for  holes  to  receive  flush  rivets 
or  countersunk  head  bolts,  this  form  of  tool  being  mainly 
employed  for  holes  above  T5g  of  an  inch  in  diameter,  A  A 


CO  UNTERSINKS.  21 3 

being  in  each  case  the  cutting  edge,  and  B  the  pin.  It 
should  be  made,  tempered,  and  used  as  directed  for  pin 
drills.  In  tempering  these  tools,  or  any  others  having  a 
pin  or  projection  to  serve  as  a  guide  in  a  hole,  the  tool 
should  be  hardened  right  out  from  the  end  of  the  pin  to 
about  I  of  an  inch  above  the  cutting  edges.  Then  lower 
the  temper  of  the  metal  (most  at  and  near  the  cutting 
edges),  leaving  the  pin  of  a  light  straw  color,  which  may 
be  accomplished  by  pouring  a  little  oil  upon  it  during  the 
lowering  or  tempering  process.  The  object  of  this  is  to 
preserve  it  as  much  as  possible  from  the  wear  due  to  its 
friction  against  the  sides  of  the  hole.  For  use  on  wrought- 
iron  and  steel,  this  countersink  (as  also  the  pin  drill)  may 
have  the  front  face  hollowed  out,  after  the  fashion  of  the 
lip  drill. 

For  use  on  holes  £  inch  and  less  in  diameter,  we  may  use 
a  countersink  made  by  turning  up  a  cone,  and  filing  upon 
it  teeth  similar  to  those  upon  a  reamer,  or  we  may  take  the 
same  turned  cone  and  cut  it  away  to  half  its  diameter,  sim- 
ilar to  a  half  round  bitt.  Either  of  these  countersinks  will 
cut  true  and  smoothly,  oil  being  applied  when  they  are 
ased  upon  steel  or  wrought-iron. 

Common  drills,  ground  to  the  requisite  angle  or  cone, 
are  sometimes  used  as  countersinks,  but  they  are  apt  to  cut 

Fig.  188. 


untrue  and  uneven.  For  fine  and  light  work,  the  pin  drill, 
with  its  cutting  edges  either  at  right  angles  to  the  centre 
line  of  the  pin  or  at  such  other  angle  as  may  be  required, 
forms  the  best  countersink  ;  it  should,  however,  have  more 


214  COMPLETE  PRACTICAL  MACHINIST. 

than  two  cutting  edges,  so  that  they  may  steady  it.  Fig. 
188  presents  an  excellent,  form  of  this  tool,  A  Uing  one 
of  the  four  cutting  edges. 

This  tool  is  formed  by  turning  up  the  whole  body,  filing 
out  the  necessary  four  spaces  between  the  cutters,  and  back- 
ing the  latter  off  at  the  ends  only,  so  that  the  circumferen- 
tial edges  will  not  cut,  and  hence  the  recesses  or  counter- 
sinks will  be  all  of  one  diameter.  When  to  be  used  upon 
steel  or  iron  only  and  not  upon  brass,  the  flutes  may  be 
given  angle,  as  in  Fig.  189,  which  will  enable  the  tool  to 
cut  more  freely.  It  is  obvious  that  the  capacity  of  tools 
of  this  class  may  be  increased  by  milking  the  pin  A  as 

small    as    is   compatible 
Fig.  189.  wjtn  strength,  and  then 

fitting  thereto  small  rings 
or  bushes,  so  as  to  vary 
the  diameter  of  the  pin 
to  suit  the  size  of  the 
hole.  Or  in  the  larger 
sizes  the  pin  may  be  let 
into  a  taper  hole  so  that  various  sizes  of  solid  pins  may 
be  used.  It  is  necessary,  however,  to  the  production  of 
round  holes  that  shall  be  of  uniform  diameter  that  the 
pins  fit  to  the  hole  without  any  play  or  lost  motion,  so  that 
the  tool  shall  not  have  liberty  to  move.  In  cases  of 
emergency  this  end  may  be  served  by  a  ferule  made  of 
sheet  tin  or  brass  merely  bent  around  upon  the  pin.  To 
ensure  the  accurate  fit  of  the  pin  to  its  hole  it  may  be 
given  cutting  edges,  and  to  facilitate  the  sharpening  of 
these  edges  a  small  hole  may  be  pierced  up  the  centre  of 
the  piii. 

CUTTERS. 

Cutters  are  steel  bits,  usually  held  in  either  a  stock  or 
bar,  being  fitted  and  keyed  to  the  same ;  by  this  means 
cutters  of  various  shapes  and  sizes  may  be  made  to  fit  one 
stock  or  bar,  thus  obviating  the  necessity  of  having  a 


CUTTERS. 


215 


multiplicity  of  these  tools.  The  end  served  by  the  use 
of  cutters  is  to  avoid  the  necessity  of  cutting  away  all 
the  metal  in  order  to  produce  the  hole,  it  being  obvious 
that  a  cutter  makes  an  annular  groove  leaving  a  ferule, 
which  falls  out  when  the  cutter  has  been  fed  entirely 
through  the  work.  The  width  of  the  cutter  edge  or  groove 
is  not  usually  more  than  about  T\  inch.  In  place  of  a 
plain,  a  tubular  cutter  is  sometimes  used.  Such  cutters, 
however,  are  expensive  to  make  and  involve  more  trouble 
to  grind  for  the  resharpening,  on  which  account  a  single 
or  a  pair  of  straight  cutters  are  generally  preferred. 
Of  cutter  stocks,  which  are  usually  employed  to  cut  holes 
of  comparatively  large  diameter,  as  in  the  case  of  tube 
plates  for  boilers,  there  are  two  kinds,  the  simplest  and 
easiest  to  be  made  being  that  shown  in  Fig.  190. 

A  is  the  stock,  through  which  runs  the  slot  or  keyway 
into  which  the  cutter  B 
fits,  being  locked  by  the  *&  19°- 

key  C.  D  is  a  pin  to 
steady  the  tool  while  it 
is  in  operation.  Holes 
of  the  size  of  the  pin  D 
are  first  drilled  in  the 
work,  into  which  the  pin 
fits.  To  obviate  the 
necessity  of  drilling  these 
holes,  some  modern  drill 
stocks  have,  in  place  of 
the  pin  D,  a  conical- 
ended  pin  which  acts  as 
a  centre,  and  which  fits 
into  a  centre  punch  mark 
made  in  the  centre  of  the 
hole  to  be  cut  in  the  work.  Most  of  these  devices  nre 
patented,  and  the  principle  upon  which  they  act  will  be 


£16 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  190o. 


understood  from  Fig.  190a,A  being  the  stock  to  which  the 
cutters  B  B  are  bolted  with  one  or  more  screws.  C  is  a 
spiral  spring  working  in  a  hole  in  the  stock  to  receive  it. 
Into  the  outer  end  of  this  hole  fits,  at  a  working  fit,  the 
centre  D,  which -is  prevented  from  being  forced  out  (from 
the  pressure  of  the  spring  C)  by  the  pin  working  in  the 
recess,  as  shown.  E  is  the  plate  to  be  cut  out,  from  which 
it  will  be  observed  that  the  centre  D  is  forced  into  the 

centre  punch  mark  in 
the  plate  by  the  spring 
C,  and  thus  serves  as  a 
guide  to  steady  the  cut- 
ters and  cause  them  to 
revolve  in  a  true  circle, 
so  that  the  necessity  of 
first  drilling  a  hole,  as 
required  in  the  employ- 
ment of  the  form  of 
stock  shown  in  Fig.  58, 
is  obviated.  The  cut- 
ters are  broadest  at  the 
cutting  edge,  which  is 
necessary  to  give  the 
point  clearance  in  the 

[  groove.     They  are  also 

at  the  taper  part  (that 

is  to  say,  the  part  projecting  below  the  stock)  made  thin- 
ner behind  than  at  the  cutting  edge,  which  is  done  to  give 
the  sides  clearance.  It  is  obvious  that,  with  suitable  cut- 
ters, various  sized  holes  may  be  cut  with  one  stock. 

In  cutting  out  holes  of  a  large  diameter  in  sheet-iron,  a 
stock  and  cutter,  such  as  shown  in  Fig.l91,is  generally  em- 
ployed ;  but  the  great  distance  of  the  cutting  edge  from  the 
stock  centre,  that  is  to  say,  the  extreme  length  of  the  cutter 
bar,  renders  it  very  liable  to  spring,  in  which  case  these 
and  other  tools  having  a  slight  body  and  broad  cutting 


CUTTERS. 


217 


Fig.  191. 


edge  are  almost  sure  to  break;  unless  some  provision  is 
made  so  that  the  tool,  in  springing,  will  recede  from  and 
not  advance  into  the  cut.  To  accomplish  this  end,  we  must 
shape  the  cutter  as  shown  in  Fig.  191, which  will,"  at  the 
very  least,  double  the  efficiency  of  the  tool. 

In  Fig.  191  the  cutting  edge  B  stands  in  the  rear  of  the 
line  A,  or  fulcrum  from 
which  the  springing  takes 
place;  hence,  when  the 
tool  springs,  it  will  recede 
from  the  work  C.  To  avoid 
springing  and  for  very 
large  holes,  the  cutter  may 
be  a  short  tool,  held  by  a 
stout  crossbar  carried  by 
thu  stock;  but  in  any  event 
the  cutter  should  be  made 
us  shown  above. 

Cutters  of  a  standard  size, 
and  intended  to  fit  the  pin 
stock,  should  be  recessed  to 
fit  the  end  of  the  slot  in 

the  stock.  In  making  these  cutters  they  should  be  first 
fitted  to  the  stock,  and  then  turned  up  in  the  lathe,  using 
the  stock  as  a  mandril,  the  ends  being  then  backed  off  to 
form  the  cutting  edges.  Those  slight  in  substance  should 
be  tempered  to  a  light  straw  at  the  cutting  edge,  and  left 
softer  at  the  back  part.  Those  above  five-sixteenths  of  an 
inch  in  thickness  may  be  hardened  right  out  and  not 
tempered  at  all. 

Here  it  may  be  as  well  to  describe  a  process  for  tem- 
pering cutters,  which,  as  several  very  expert  workmen 
have  assured  me,  gives  superior  results.  It  is  to  heat  the 
cutter  to  a  cherry-red  heat,  and  quench  it  in  water  until 
it  is  cold,  and  to  then  reheat  it  until  water  dropped  upon 
it  will  dry  off  in  slight  bubbles.  If,  however,  the  reheat- 
19  - 


218  COMPLETE  PRACTICAL  MACHINIST. 

ing  is  rapidly  performed,  there  will  be  no  need  to  drop  any 
water  on  it,  since  that  which  adheres  to  it  after  quenching 
will  be  sufficient.  I  have  no  doubt  but  that  for  stout 
cutters,  or  even  for  slight  ones  which  perform  a  light  duty, 
this  method  is  preferable  to  all  others:  but  for  light 
cutters  performing  a  heavy  duty,  I  should  judge  that  it 
would  leave  them  too  hard  for  their  strength,  and  there- 
fore liable  to  break. 

Cutters  for  boring  bars  should  be,  if  intended  to  be  of 
standard  size,  recessed  to  fit  the  bar,  the  bar  having  a  flat 
place  filed  around  and  beyond  the  edges  of  the  hole,  to 
form  a  broader  bearing  for  the  cutter  to  fit  upon.  But,  if 
the  cutter  is  intended  to  vary  the  size  of  hole,  it  niugt 
be  left  plain,  so  that  it  may  be  moved  inwards  or  outwards 
to  accommodate  the  size  of  bore  required.  All  cutters  and 
bits  should  be  used  at  a  cutting  speed  of  about  15  feet  per 
minute,  and  with  oil  or  soapy  water  for  woik  in  wrought- 
irou  or  steel ;  and  for  use  on  those  metals,  the  cutters,  etc., 
may  be  given  a  little  front  rake  by  grinding  away  the 
metal  of  the  front  face,  as  shown  by  the  dotted  line  in  Fig. 
190,  at  E. 


CHAPTER    XII. 

TOOL   STEEL. 

THE  cutting  tools  for  all  machines  should  be  made  of 
hammered  (which  is  tougher  and  of  finer  grain  than  rolled) 
steel.  Even  in  a  bar  of  hammered  steel,  the  corners,  from 
receiving  the  most  effect  from  the  action  of  the  hammer, 
are  of  better  quality  (that  is,  more  refined)  than  the  rest 
of  the  bar.  This  fact  is  clearly  demonstrated  in  the  manu- 
facture of  the  celebrated  Damascus  swords  and  gun  bar- 
rels, in  which  the  square  bars  of  metal  are,  after  being 
hammered,  twisted  and  then  hammered  square  again ;  the 
twisting  process  is  then  repeated,  and  the  bar  again  forged 
square,  the  whole  operation  being  repeated  until  the  body 
of  the  entire  bar  is  completely  intersected  with  metal 
which  has,  at  some  time  during  the  forging  process,  formed 
the  corners  of  a  square.  The  effect  of  this  treatment 
becomes  apparent  upon  immersing  the  metal  in  acid,  which 
will  eat  away  those  parts  which  have  not  formed  a  corner 
at  some  stage  of  the  process  of  manufacture,  more  rapidly 
than  the  rest  of  the  metal,  and  that  to  such  a  degree  as  to 
give  to  the  whole  the  appearance  of  having  been  engraved, 
thus  evidencing  that  the  parts  that  have  received  the  most 
hammering  are  of  finer  quality  than  the  rest  of  the  bar. 

For  cutting  tools,  it  is  highly  necessary  to  gain  every 
attainable  superiority  in  the  steel ;  and  if  we  cannot  take 
three  months  of  time  to  prepare  bars  for  this  special  pur- 
pose (as  they  do  in  the  above  process),  we  can  at  least 
employ  well-hammered  steel,  and  thus  secure  the  best 

known  practicable  results. 

219 


220  COMPLETE  PRACTICAL  MACHINIST. 

The  test  of  tool  steel  is  the  speed  at  which  it  will  cut 
and  the  length  of  time  it  will  last  without  being  ground, 
concerning  which  it  is  difficult  to  get  data,  unless  by  actual 
experiment  with  different  kinds  of  steel  upon  work  of  the 
same  diameter  and  texture  of  metal,  because  the  cutting 
speed  employed  by  workmen  varies  as  much  as  10  feet  per 
minute  upon  the  same  diameter  of  work.  The  use  of  more 
than  one  kind  of  tool  steel  in  a  workshop  should  always  be 
avoided,  because  different  kinds  of  steel  require  different 
treatment,  both  in  forging  and  hardening ;  and  when  more 
than  one  kind  is  in  use  in  the  shop,  the  whole  of  them 
are  liable  (from  not  noticing  the  particular  brand)  to 
wrong  treatment. 

Mushet's  "  special  tool  steel "  makes  an  excellent  tool  for 
roughing  work  out  on  the  lathe  or  planer,  and  will  undoubt- 
edly stand  a  higher  rate  of  cutting  speed  than  other  steel. 
For  turning  shafting  and  cast-iron  pulleys,  especially  when 
the  latter  are  unusually  hard,  this  tool  works  admirably.  Its 
peculiarity  is  that  it  is  hard  of  itself,  and  therefore  requires 
no  hardening.  Immersing  it  in  water  when  it  is  heated 
causes  it  to  crack.  The  advantages  claimed  for  it  are  its 
high  rate  of  cutting  speed,  and  that  it  is  easily  ground, 
since  it  will  not  soften  by  heating  during  the  operation. 
It  is,  on  the  other  hand,  difficult  to  forge  in  consequence 
of  its  excessive  hardness  even  when  heated ;  it  must  not 
be  forged  at  so  great  or  so  low  a  temperature  as  other 
steel,  or  it  will  crack  ;  and  as  it  is  not  adapted  for  general 
tool  purposes,  its  disadvantages,  independent  of  its  increased 
cost,  render  its  introduction  into  the  general  machine-shop 
uuadvisable. 

FORGING   TOOLS. 

The  forging  of  a  tool  should  be  fqtmed  in  as  few  heats 
as  possible,  for  steel  deteriorates  by  repeated  heating, 
unless  it  is  well  hammered  at  each  heat ;  and  if  the  tool 
has  a  narrow  edge,  care  should  also  be  taken  to  hammer  it 
on  that  edge  before  fhe  metal  has  lost  much  of  its  heat, 


FORGING   TOOLS.  221 

and  to  strike  it  more  lightly  as  it  gets  cooler,  for  striking 
a  narrow  surface  of  steel  when  it  is  somewhat  cool  has  the 
same  injurious  eifect  upon  it  as  striking  it  endwise  of  the 
grain  (which  is  termed  upsetting  it),  destroying  its  cutting 
value  and  strength. 

If  the  tool  requires  much  drawing  out,  the  steel  should 
be  drawn  rectangular  to  as  near  as  possible  the  required 
size,  leaving  only  sufficient  metal  to  shape  up  the  tool. 
The  steel  should  be  heated  to  a  light-red  and  in  no  case  to 
a  yellow  heat,  which  would  cause  it  to  become  what  is 
termed  "  burnt,"  after  which  its  cutting  value  is  irretriev- 
ably lost,  nor  will  any  amount  of  forging  restore  it  to  its 
former  standard.  A  tool  that  has  been  accidentally  over- 
heated should  have  the  burnt  part  cut  off  and  be  entirely 
reforged.  Front  or  other  tools  for  use  on  wrought-iron 
should  be  forged  as  follows :  Draw  the  bar  steel  down 
taper  on  one  edge  of  the  steel  and  parallel  on  the  other, 
and  then  bend  the  cutting  part  of  the  tool  up  so  that  the 
tool  will  bear  the  shape  of  Figs.  4,  5,  6,  and  7,  which 
are  better  and  more  easily  forged  tools  than  those  shown 
by  Figs.  9, 19,  and  18,  the  latter  being  fae  similes  of  the 
forms  of  tools  in  use  at  the  Morgan  Iron  Works.  They 
are  of  perfectly  correct  form  so  far  as  the  shapes  of  the 
cutting  edges  are  concerned,  but  are  more  difficult  to  forge 
and  to  grind  than  the  former,  which  are  again  superior  in 
that  the  height  of  their  cutting  edges  from  the  bottom 
edge  is  less,  and  hence  they  do  not  surfer  so  much  from  the 
causes  explained  by  Figs.  24  and  25  and  their  accompany- 
ing remarks.  It  is  obvious,  however,  that  the  height  of 
the  tool  edge  from  the  bottom  face  of  a  lathe  tool  is  deter- 
mined by  the  height  of  the  face  of  the  slide  rest  on  which 
the  tool  rests  from  the  horizontal  centre  of  the  lathe 
centres. 

In  using  American  chrome  steel,  be  careful  to  forge  it 
according  to  the  directions  supplied  by  its  manufacturers, 
its  treatment  being  almost  the  opposite  for  that  applicable 
19  > 


222  COMPLETE  PRACTICAL  MACHINIST. 

to  English  tool  steel,  the  former  requiring  to  be  heated  to 
a  much  higher  temperature  for  forging,  and  to  a  less  tem- 
perature for  hardening,  than  the  latter. 

\^   . 

TOOL  HARDENING  AND  TEMPERING. 

Steel  is  said  to  be  hardened  when  it  is  as  hard  as  it  is 
practicable  to  make  it,  and  to  be  tempered  when,  after 
having  been  hardened,  it  is  subjected  to  a  less  degree  of 
heat,  which  partly  but  not  altogether  destroys  or  removes 
the  hardness.  The  degree  to  which  this  tempering  is  per- 
formed, or  in  other  words  the  degree  of  the  temper,  is  made 
perceptible  and  estimated  as  follows :  By  heating  a  piece 
of  steel  to  a  red  heat  (not  so  hot  as  to  cause  it  to  scale), 
and  then  plunging  it  into  cold  water  and  allowing  it  to 
remain  there  until  it  is  cold,  it  will  be  hardened  right  out, 
as  it  is  termed,  that  is,  it  will  be  made  hard  to  the  greatest 
practicable  degree.  If  it  is  then  slowly  reheated,  its  outer 
surface  will,  as  the  temperature  increases,  assume  various 
shades  of  color,  commencing  with  a  very  light  straw  color, 
which  deepens  successively  to  a  deep  yellow,  red,  brown, 
purple,  blue,  and  green,  which  latter  fades  away  as  the 
steel  becomes  heated  to  redness  again,  when  the  effects  of 
the  first  hardening  will  have  been  entirely  removed.  It 
becomes  apparent,  then,  that  the  colors  which  appear  upon 
the  surface  of  the  steel  denote  the  degree  to  which  the  tem- 
pering or  resoftening  operation  has  taken  place.  Having 
then  by  practice  ascertained  the  color  which  denotes  the 
particular  degree  of  hardness  requisite  for  any  specified 
tool,  we  are  enabled  to  always  temper  it  to  that  degree, 
sufficiently  near  for  all  practical  purposes.  It  is  un- 
doubtedly true  that,  if  the  conditions  of  tempering  which 
will  be  laid  down  in  all  our  instructions  are  (for  want  of 
sufficient  experience  in  the  operator)  varied,  the  colors  will 
not  present,  to  positive  exactitude,  the  precise  degree  of 
temper :  the  difference  being  that,  if  the  color  forms  very 
rapidly,  the  tool  may  be  left  of  a  lighter  color;  and  that  if 


TOOL    TEMPERING.  223 

the  colors  form  very  slowly,  the  tool  may  be  left  of  a 
slightly  deeper  hue.  The  difference  in  temper,  however, 
as  compared  to  the  color,  will  in  no  case  be  sufficient  to  be 
perceptible  in  ordinary  tool  practice,  and  need  not,  save 
under  circumstances  requiring  great  minuteness  in  the 
degree  of  temper,  be  paid  any  attention  to. 

When  a  tool  such  as  a  drill  requires  to  be  tempered  at 
and  near  the  cutting  edge  only,  and  it  is  desirable  to  leave 
the  other  part  or  parts  soft,  the  tempering  is  performed  by 
heating  the  steel  for  some  little  distance  back  from  the 
cutting  edge,  and  then  immersing  the  cutting  edge  and 
about  one-half  of  the  rest  of  the  steel,  which  is  heated  to  as 
high  a  degree  as  a  red  heat,  in  the  water  until  it  is  cold  ; 
then  withdraw  the  tool  and  brighten  the  surface  which  has 
been  immersed  by  rubbing  it  with  a  piece  of  soft  stone 
(such  as  a  piece  of  a  worn-out  grindstone)  or  a  piece  of 
coarse  emery  cloth,  the  object  of  brightening  the  surface 
being  to  cause  the  colors  to  show  themselves  distinctly. 
The  instant  this  operation  has  been  performed  the  bright- 
ened surface  should  be  lightly  brushed  by  switching  the 
finger  rapidly  over  it ;  for  unless  this  is  done,  the  colors 
appearing  will  be  false  colors,  as  will  be  found  by  neglect- 
ing this  latter  operation,  in  which  case  the  steel  after 
quenching  will  be  of  one  color ;  and  if  then  wiped,  will 
appear  of  a  different  hue.  A  piece  of  w-aste  or  other 
material  may  of  course  be  used  in  place  of  the  hand.  The 
heat  of  that  part  of  the  tool  which  has  not  been  immersed 
will  become  imparted  to  that  part  which  was  hardened, 
and,  by  the  deepening  of  the  colors,  denote  the  point  of 
time  at  which  it  is  necessary  to  again  immerse  the  tool 
and  quench  it  altogether  cold. 

The  operation  of  the  first  dipping  requires  some  little 
judgment  and  care ;  for  if  the  tool  is  dipped  a  certain  dis- 
tance and  held  in  that  position  without  being  moved  till 
the  end  dipped  is  cold,  and  the  tempering  process  is  pro- 
ceeded with,  the  colors  from  yellow  to  green  will  appear  in 


224  COMPLETE  PRACTICAL  MACHINIST. 

a  narrow  band,  and  it  will  be  impossible  to  directly  per- 
ceive when  the  cutting  edge  is  at  the  exact  shade  of  color 
required ;  then  again,  the  breadth  of  metal  of  any  one 
degree  of  color  will  be  so  small  that  once  grinding  the  tool 
will  remove  it  and  give  us  a  cutting  edge  having  a  different 
degree  of  temper  or  of  hardness.  The  first  dipping  should 
be  performed  thus :  Lower  the  tool  vertically  into  the 
water  to  about  one-third  of  the  distance  to  which  it  is  red 
hot,  hold  it  still  for  about  sufficient  time  to  cool  the  end 
immersed,  then  suddenly  plunge  it  another  third  of  the 
distance  to  which  it  is  heated  red,  and  withdraw  it  before 
it  has  had  time  to  become  more  than  half  cooled.  By  this 
means  the  body  of  metal  between  the  cutting  edge  and  the 
part  behind,  which  is  still  red  hot,  will  be  sufficiently  long 
to  cause  the  variation  in  the  temperature  of  the  tool  end  to 
be  extended  in  a  broad  band,  so  that  the  band  of  yellow 
will  extend  some  little  distance  before  it  deepens  into  a 
red ;  hence  it  will  be  easy  to  ascertain  when  the  precise 
degree  of  color  and  of  temper  is  obtained,  when  the  tool 
may  be  entirely  quenched.  A  further  advantage  to  the 
credit  of  this  plan  of  dipping  is  that  the  required  degree 
of  hardness  will  vary  but  very  little  in  consequence  of 
grinding  the  tool ;  and  if  the  operation  is  carefully  per- 
formed, the  tool  can  b-3  so  tempered  that,  by  the  time  the 
tool  has  lost  the  required  degree  of  temper  from  being 
ground  back,  it  will  also  require  reforging  or  reforming. 
As  a  rula  a  tool  should  be  made  to  a  red  heat  to  a  distance 
about  twice  the  diameter  of  the  tool  steel  of  which  it  is 
made. 

The  degree  to  which  a  tool  may  be  hardened  is  dependent 
in  a  great  measure  upon  its  shape.  The  only  reason  for 
tempering  any  lathe  tool  is  to  stre-ngthen  it,  for  steel  har- 
dened right  out  is  comparatively  weak  and  gains  strength 
by  being  tempered.  The  lower  the  temper  the  greater  the 
strength.  A  straw  color  is  well  adapted  to  ordinary  light 
tools,  but  very  slight  tools,  such  as  say  a  parting  tool  ^ 


TOOL   TEMPERING.  225 

inch  wide,  may  be  lowered  to  a  deep  brown  or  almost  to  a 
purple.  Stout  tools,  such  as  are  shown  in  Fig.  2,  may  be 
made  as  hard  as  fire  and  water  will  make  them ;  so  also 
may  the  tools  presented  in  Figs.  8,  9,  18,  19,  28,  and  34 ; 
while  slight  tools,  such  as  are  given  in  Figs.  29  and  30, 
should  be  lowered  in  temper  to  a  light  straw  color. 

The  practice  of  lowering  stout  tools  to  a  straw  color  is 
sometimes  resorted  to,  but  it  is  certainly  an  error,  for  it  is 
undoubtedly  advantageous  to  make  the  tool  as  hard  as  it 
can  be  made,  so  long  as  it  will  bear  the  strain  of  the  cut, 
which  is  possible  and  easy  of  accomplishment  with  Jes- 
sop's,  Moss',  Sanderson's,  or  other  similar  grades  of  tool 
steel. 

If  a  tool  so  hardened  is  found  to  break,  it  is  in  conse- 
quence either  of  its  being  bad  steel  or  else  it  has  been 
heated  to  too  great  a  temperature  in  the  process  of  forging 
or  hardening,  unless  it  has  been  given  too  much  rake  for 
the  duty  to  which  it  has  been  allotted.  Tool  steel  may  be 
forged  at  such  a  temperature  that  it  is  not  positively 
burned,  and  yet  has  lost  part  of  its  virtue ;  and  while  under 
such  circumstances  it  would  break  if  hardened  right  out,  it 
will  cut  and  stand  moderately  well  if  the  temper  be  lowered 
to  a  straw  color. 

This  is  simply  sacrificing  the  degree  of  hardness  to  cover 
the  blunder  committed  by  overheating,  and  it  is  from  such 
causes  that  the  variation  of  cutting  speed  employed  by 
mechanics  arises ;  for  a  youth  who  has  learned  his  trade  in 
a  shop  where  the  tools  were  overheated,  and  consequently 
underhardened,  settles  down  to  the  rate  of  cutting  speed 
attainable  under  those  circumstances  and  adheres  to  it; 
while  he  who  has  been  accustomed  to  the  use  of  tools  prop- 
erly forged  and  hardened  right  out,  upon  entering  another 
shop  where  the  tools  are  overheated  in  forging  and  under- 
hardened  to  compensate  for  it,  finding  he  cannot  get  the 
cutting  speed  up  to  his  customary  rate,  breaks  off*  the  tool 
point  to  see  if  it  has  been  burned,  and,  finding  that  the 


226  COMPLETE  PRACTICAL  MACHINIST. 

grain  of  the  metal  does  not  appear  granulated,  sparkling, 
and  coarse,  as  it  would  do  if  positively  burned,  condemns 
the  quality  of  the  steel. 

The  grain  of  properly  forged  and  hardened  tool  steel 
appears,  when  fractured,  close  and  fine,  and  of  a  dull, 
whitish  tint,  the  fracture  being  even  on  its  surface. 

American  chrome  tool  steel  may  be  made  unusually 
hard  by  using  very  clean  wrater  and  adding  a  piece  of 
fuller's  earth  and  a  piece  of  common  soda,  each  of  the  size 
of  a  hazel  nut,  to  a  pailful  of  water. 

In  all  cases  where  a  tool  can  be  ground  to  sharpen  it,  it 
should  be  hardened  before  grinding,  for  steel  hardened  with 
the  forged  skin  on  is  stronger  and  better  than  that  in  which 
the  skin  is  removed  before  hardening.  When  it  is  intended 
to  harden  a  tool  right  out,  heat  it  to  a  cherry  red  to  the 
distance  that  it  is  necessary  to  harden  it,  and  plunge  it  into 
the  water  suddenly  to  the  distance  it  requires  hardening ; 
hold  it  still  a  moment,  then  dip  it  a  little  deeper,  and  with- 
draw it  again  to  the  amount  of  the  last  dipping,  repeating 
this  latter  operation  until  the  tool  is  cold  ;  for  by  this  means 
the  junction  of  the  hard  and  soft  steel  in  the  tool  is  gradu- 
ated and  not  sharply  defined,  the  result  being  that  the  tool 
is  less  liable  to  fracture  either  in  hardening  or  in  using. 
If  the  tool  to  be  hardened  has  a  thick  part  to  it,  let  that 
part  enter  the  water  first  and  immerse  the  tool  slowly,  so 
that  it  will  be  cooled  as  nearly  equally  as  possible  and  thus 
be  prevented  from  cracking  in  hardening. 

Tools  heated  by  charcoal  are  much  superior  to  those 
heated  by  common  coal,  and  need  not  be  made  quite  so 
hot  to  harden.  To  harden  steel,  never  get  it  hot  enough 
to  cause  it  to  scale.  Thin  pieces  of  steel,  and  taps,  dies, 
reamers,  drifts,  and  similarly  shaped  tools,  should  be  dip] KM! 
endways  ;  for  if  dipped  otherwise,  they  are  sure  to  warp  in 
hardening.  Very  slight  tools  may  be  prevented  from  crack- 
ing by  making  the  water  quite  warm  before  immcirin^ 
them,  and  then  holding  them  still  in  the  water ;  in  fact,  all 


HARDENING  SPRINGS.  22" 

water  for  hardening  purposes  should  have  the  chill  off  it 
by  heating,  before  being  used,  or  the  articles  hardened  in 
it  are  very  liable  to  crack.  If  the  article  requires  to  be 
hardened  all  over,  immerse  it  (suspended  on  a  wire  hook) 
so  that  the  water  may  have  free  and  equal  access  to  the 
whole  surface  of  the  steel,  which  is  not  possible  with  tongs 
in  consequence  of  their  jaws  covering  part  of  the  steel. 

HARDENING. 

All  work  to  be  hardened  should  be  heated  according  to 
its  shape,  the  work  being  so  manipulated  in  the  fire  that 
the  thin  parts  do  not  get  to  the  required  heat  before  the 
thick  parts  do.  Then  in  quenching  them  in  the  water  the 
thick  parts  should  be  immersed  first,  and  the  operation  be 
performed  slowly.  The  work  should  be  lowered  perpen- 
dicularly in  the  water  and  immersed  deeply,  and  not  under 
any  circumstances  moved  sideways.  Uneven  heating  warps 
the  work  in  the  fire,  careless  dipping  warps  and  cracks  it 
in  the  hardening.  Always  use  water  that  is  at  least  luke- 
warm, and  if  the  article  has  one  part  much  thinner  than 
another,  or  is  very  slight,  and  hence  liable  to  warp  or 
crack,  make  the  water  a:3  hot  as  the  hand  will  bear  it,  and 
dip  the  work  edgeways,  the  heaviest  side  being  downwards. 
Very  small  articles  to  be  hardened  in  quantities  may  be 
heated  in  a  piece  of  wrought-iron  pipe,  having  one  end 
closed,  the  pipe  being  revolved  in  the  fire  during  the  heat- 
ing process  to  equalize  the  heating  of  the  work. 

TO    HARDEN   SPRINGS. 

Small  springs,  which  should  be  made  of  spring-steel  or 
double-shear  steel,  may  be  hardened  as  follows:  Heat 
them  to  a  bright  cherry-red,  and  quench  them  in  water 
having  the  cold  chill  taken  off  it.  If,  on  being  taken  from 
the  water,  they  are  white,  or  mottled  with  white  and  a 
light  gray,  they  are  hard  enough,  but  if  they  are  dark- 
colored,  they  are  not  hard  enough,  and  must  be  rchard- 


228  COMPLETE  PRACTICAL  MACHINIST. 

erred.  After  'being  hardened,  they  may  be  tempered  as 
follows :  String  them,  if  possible,  on  a  wire,  and  fry  them 
over  the  fire  in  a  pan  or  tray  containing  enough  lard  oil  to 
well  cover  them, -and  heat  the  oil  until  it  will  blaze  all 
over  the  surface,  then  turn  the  springs  over  and  over  in 
the  blazing  oil,  letting  them  blaze  long  enough  to  be  sure 
that  the  thick  parts  of  the  spring  are  equally  heated  with 
the  thin  parts.  If  a  single  spring  requires  tempering,  it 
may  be  tempered  by  fastening  it  to  a  wire,  and  just  above 
it  put  a  small  roll  of  wire  to  retain  the  oil.  Heat  the 
spring  over  a  very  slow  fire,  and  apply  oil,  letting  it  run 
down  the  wire  to  the  spring.  Keep  the  spring  supplied 
with  oil,  and  let  it  blaze  a  minute  or  so.  If  it  has  a  light 
or  thin  part  to  it,  pour  cold  oil  on  that  part  of  it  during 
the  early  part  of  the  blazing  process. 

Large  springs  are  first  hardened,  and  then  blazed  off  in 
whale  oil,  containing  2  Ibs.  of  tallow  and  \  Ib.  of  beeswax 
(or,  instead  of  the  latter,  \  Ib.  of  black  resin)  to  every 
gallon  of  whale  oil.  If  a  spring  is  made  of  cast-steel  it 
must,  after  blazing  off,  be  left  to  cool  of  itself  without  being 
quenched  off. 

Springs  that  have  the  forged  skin  on  are  stronger  and 
more  elastic  than  those  which  are  brightened,  and  all 
springs  are  reduced  in  elasticity  by  grinding  off  the  sur- 
face after  they  are  tempered ;  especially,  however,  is  this 
the  case  with  those  having  the  forged  or  rolled  skin  on. 

To  harden  machine-steel,  or  make  cast-steel  very  hard, 
put  a  pound  of  salt  to  a  gallon  of  rain-water. 

The  longer  water  or  a  tempering  liquid  is  used  the  better 
it  becomes,  but  either  of  them  are  wholly  spoiled  if  any 
greasy  substance  gets  in  them. 

All  steel,  as  well  as  iron,  swells  by  hardening,  so  that 
holes  become  smaller,  and  outside  surfaces  larger,  in  conse- 
quence of  hardening,  and  this  fact  is  often  taken  advantage 
of  to  refit  iron  or  steel  work  that  has  become  worn.  For 
instance,  suppose  a  bolt  has  worn  loose :  the  bolt  may  be 


CASE  HARDENING.  229 

hardened  by  the  common  prussiate  of  potash  process,  which 
will  cause  it  to  increase  in  size,  both  in  length  and  diam- 
eter. The  hole  may  be  also  hardened  in  the  same  way, 
which  will  decrease  its  diameter ;  and  if  the  decrease  is 
more  than  necessary,  the  hole  may  be  ground  or  "lapped" 
out  by  means  of  a  lap.  Only  about  gV  of  an  inch  of 
shrinkage  can  be  obtained  on  a  hole  and  bolt  by  harden- 
ing, which,  however,  is  highly  advantageous  when  it  is  suf- 
ficient, because  both  the  hole  and  the  bolt  will  wear  longer 
for  being  hardened. 

CASE-HARDENING   WROUGHT-IRON. 

Iron  may  be  case-hardened,  that  is,  the  surface  converted 
into  steel  and  hardened,  as  follows :  First,  by  the  common 
prussiate  of  potash  process,  which  is  as  follows :  Crush  the 
potash  to  a  powder,  being  careful  that  there  are  no  lumps 
left  in  it,  then  heat  the  iron  as  hot  as  possible  without  caus- 
ing it  to  scale ;  and  with  a  piece  of  rod  iron,  spoon-shaped 
at  the  end,  apply  the  prussiate  of  potash  to  the  surface  of 
the  iron,  rub  it  with  the  spoon  end  of  the  rod  uatil  it  fuses 
and  runs  all  over  the  article,  which  must  then  be  placed  in 
the  fire  again  and  slightly  reheated,  and  then  plunged  into 
water,  observing  the  rules  given  for  immersing  steel  so  as 
not  to  warp  the  article.  = 

Another  method  is  to  place  the  pieces  to  be  hardened  in 
an  iron  box,  made  air-tight  by  having  all  its  seams  covered 
well  with  fire  clay,  filling  the  box  in  with  bone  dust  closely 
packed  around  the  articles,  or  (what  is  better)  with  leather 
and  hoofs  cut  into  pieces  about  an  inch  in  size,  adding  thin 
layers  of  salt  in  the  proportion  of  about  4  Ibs.  salt  to  20 
Ibs.  of  leather  and  15  Ibs.  of  hoofs.  In  packing  the  articles 
in  the  box,  be  careful  to  so  place  them  that  when  the  hoofs, 
leather,  etc.,  are  burned  away,  and  the  pieces  of  iron  in  the 
box  receive  the  weight  of  those  above -them,  they  will  not 
be  likely  to  bend  from  the  pressure.  When  the  articles  are 
packed  and  the  box  ready  to  be  closed  with  the  lid,  pour 
20 


230  COMPLETE  PRACTICAL  MACHINIST. 

into  it  one  gallon  of  urine  to  the  above  quantities  of  leather, 
etc. ;  then  fasten  down  the  lid  and  seal  the  seams  outside 
well  with  clay.  The  box  is  then  placed  in  a  furnace  and 
allowed  to  remain  there  for  about  12  hours,  when  the  arti- 
cles are  taken  out  and  quickly  immersed  in  water,  care 
being  taken  to  put  them  in  the  water  endways  to  avoid 
warping  them. 

Articles  to  be  case-hardened  in  tha  above  manner  should 
have  pieces  of  sheet-iron  fitted  in  them  in  all  parts  where 
they  are  required  to  fit  well  and  are  difficult  to  bend  when 
cold,  and  the  heaviest  pieces  of  work  should  be  put  at  the 
bottom  of  the  box. 

THE   WEAR   OF   METAL  SURFACES. 

The  wear  of  metal  surfaces,  such  as  cast-iron,  wrought- 
iron,  steel,  and  brass,  is  governed  as  much  by  the  conditions 
under  which  that  wear  takes  place  as  it  is  by  the  degree 
of  hardness  of  the  metal. 

It  is  a  general  rule,  that  motion  in  one  continuous  direc- 
tion causes  more  wear,  under  equal  conditions,  than  does  a 
reciprocating  motion,  and  also  that  the  harder  the  metal 
the  less  the  wear.  To  this  latter  rule  there  are,  however, 
exceptions  in  favor  of  cast-iron,  which  will  wear  better  when 
surrounded  by  steam  than  will  any  other  metal.  Thus,  for 
instance,  experience  has  demonstrated  that  piston-rings  of 
cast-iron  will  wear  smoother,  better,  and  equally  as  long  as 
those  of  steel,  and  longer  than  those  of  either  wrought-iron 
or  brass,  whether  the  cylinder  in  which  it  works  be  com- 
posed of  brass,  steel,  wrought-iron,  or  cast-iron — the  latter 
being  the  more  noteworthy,  since  two  surfaces  of  the  same 
metal  do  not,  as  a  rule,  wear  or  work  well  together.  So 
also  slide-valves  of  brass  are  not  found  to  wear  so  long  or 
so  smoothly  as  those  of  cast-iron,  let  the  metal  of  which  the 
seating  is  composed  be  whatever  it  may  ;  while,  on  the  other 
hand,  a  cast-iron  slide-valve  will  wear  longer  of  itself,  and 
cause  less  wear  to  its  scat,  if  the  latter  is  of  cast-iron,  than 


THE   WEAR  OF  METAL  SURFACES.  231 

if  of  steel,  wrought-iron,  or  brass.  The  duty  in  each  of  these 
cases  is  light ;  the  pressure  on  the  cast-iron,  in  the  first  in- 
stance cited,  probably  never  exceeding  a  pressure  of  ten 
pounds  per  inch,  while,  in  the  latter  case,  two  hundred 
pounds  per  square  inch  of  area  is  probably  the  extreme 
limit  under  which  slide-valves  work ;  and  what  the  result 
under  much  heavier  pressures  would  be  is  entirely  proble- 
matical. 

Cast-iron  in  bearings  or  boxes  is  found  to  work  exceed- 
ingly smoothly  and  well  under  light  duty,  provided  the 
lubrication  is  perfect  and  the  surfaces  can  be  kept  practi- 
cally free  from  grit  and  dust.  The  reason  of  this  is,  that 
cast-iron,  especially  that  of  American  manufacture,  forms  a 
hard  surface-skin,  when  rubbed  under  a  light  pressure,  and 
so  long  as  the  pressure  is  not  sufficient  to  abrade  this  hard 
skin,  it  will  wear  bright  and  very  smooth,  becoming  so  hard 
that  a  scraper  made  as  hard  as  fire  and  water  will  make  it 
will  scarcely  cut  the  skin  referred  to.  Thus,  in  making 
cast-iron  and  wrought-irou  surface-plates  or  plauometer.-", 
we  may  rub  two  such  plates  of  cast-iron  together  under 
moderate  pressure  for  an  indefinite  length  of  time,  and  tho 
tops  of  the  scraper-marks  will  become  bright  and  smooth, 
but  will  not  wear  off;  while  if  we  rub  one  of  cast-iron  and 
one  of  wrought-iron,  or  two  of  wrought-iron,  well  together, 
the  wrought-iron  surfaces  will  abrade  so  that  the  protruding 
scraper-marks  will  entirely  disappear,  while  the  slight 
amount  of  lubrication  placed  between  such  surfaces  to  pre- 
vent them  from  cutting  will  become,  in  consequence  of  the 
presence  of  the  wrought-iron,  thick  and  of  a  dark-blue 
color,  and  will  cling  to  the  surfaces,  so  that  after  a  time  it 
becomes  difficult  to  move  the  one  surface  upon  the  other. 
If,  however,  the  surfaces  are  pressed  together  sufficiently  to 
abrade  the  hard  skin  from  the  cast-iron,  a  rapid  cutting 
immediately  takes  place,  which  is  very  difficult  to  remove, 
the  only  remedy  being  to  entirely  remove  the  particles  of 
metal  due  to  the  abrasion,  and  lubricate  very  freely. 


232  COMPLETE  PRACTICAL  MACHINIST. 

Under  a  light  duty,  cast-iron,  especially  when  working 
under  steam  pressure,  will  wear  longer  and  better  than 
brass,  wrought-iron  or  steel,  even  if  the  motion  be  continu- 
ously in  one  direction ;  thus,  for  revolving  side-surfaces, 
such  as  discs,  it  retains  its  superiority  over  the  harder 
metals,  and  there  is  no  test  so  great  as  is  involved  under 
such  conditions,  for  the  following  reasons : 

Suppose  we  have  a  piston  revolving  in  a  cylinder.  The 
metal  on  the  piston,  at  a  distance  of  2  inches  from  its  cen- 
tre, will  pass  over  a  circle,  in  the  cylinder,  of  12,566  inches 
in  circumference.  The  metal  on  the  piston,  however,  at  a 
distance  of  4  inches  from  its  centre,  will  pass  over  a  circle 
or  surface  of  a  circumference  of  25,132  inches.  Thus,  we 
find  the  one  part  of  the  piston  to  pass  over  twice  as  much 
metal  as  does  the  other  in  performing  a  revolution,  making 
the  wear  on  that  account  twice  as  great  at  the  large  radius 
as  it  is  at  the  small  one.  But  this  is  not  all,  for  the  metal 
at  the  large  radius  travelled  over  its  wearing  surface,  that 
is  to  say,  the  surface  it  bears  against,  in  making  a  revolu- 
tion, at  a  speed  twice  as  great  as  did  the  metal  at  the  small 
one  over  its  wearing  surface,  since  one  travelled  over  six- 
teen inches  in  the  same  time  that  the  other  travelled  over 
eight  inches  of  surface ;  this  increase  further  doubles  the 
wear  at  the  large  radius,  making  its  wear  fourfold  that  at 
the  small  one,  and  giving  us  the  rule  that  the  wear  of  a 
revolving  disc  increases  (as  does  its  area)  in  the  ratio  of 
the  square  of  its  diameter.  The  result  of  this  inequality  of 
wear  was  demonstrated  in  the  early  days  of  locomotive- 
engineering,  at  which  time  the  throttle-valves  were  in 
nearly  all  engines  semi-revolving  discs,  with  radial  open- 
ings, the  wearing  surfaces  being  on  the  side  face,  and  the 
disc  revolving  reciprocally  on  a  centre-pin. 

The  result  of  the  wear  on  such  valves  was  found  to  be 
very  unsatisfactory,  because  the  metal  at  and  near  the 
extreme  circumference  would  wear  very  rapidly  away. 
The  pressure  of  the  steam,  however,  by  springing  the  outer 


REVOLVING   SURFACES.  233 

surface  of  the  disc  to  its  seat,  would  prevent  the  faces  from 
leaking,  but  the  pressure  of  the  outer  diametrical  surface  to 
its  seat  would  be  diminished  in  proportion  to  the  resistance 
of  the  metal  to  the  spring  referred  to,  and,  as  a  consequence, 
the  surface  of  the  metal  at  and  near  the  centre  of  the  disc 
would  have  upon  its  bearing  surface  not  only  the  pressure 
due  to  the  steam  acting  upon  its  exposed  surface,  but  an 
amount  in  excess  equal  to  that  to  which  the  outer  diameter 
was  relieved  in  consequence  of  its  resistance  to  spring. 

These  conditions  would  continue  until  the  wear  of  the 
larger  diameter  becoming  greater,  and  the  amount  of  spring 
required  to  keep  it  to  its  seat  increasing  in  proportion,  the 
resistance  of  the  metal  to  so  much  spring  partly  relieves 
the  pressure  of  the  larger  diameter  to  its  seat,  and  since  the 
pressure  due  to  the  force  exerted  by  the  steam  upon  the 
exposed  surface  of  the  disc  will  remain  constant,  to  what- 
ever amount  the  outer  diameter  is  relieved  of  the  pressure 
to  its  seat,  that  at  and  near  the  centre,  forcing  it  to  its  seat, 
will  be  augmented,  until  at  last  the  excessive  pressure  will 
cause  it  to  cut  or  abrade,  which  action  will  continue  until 
the  cutting  at  and  about  the  centre  will  allow  the  larger 
diameter  to  bed  with  more  force  to  its  seat,  by  diminishing 
the  amount  of  its  spring,  and  hence  its  resistance  to  the 
steam-pressure  immediately  behind  it,  whereupon  its  exces- 
sive wear  would  recommence. 

If,  however,  the  thickness  of  the  disc  were  made  such  as 
to  enable  it  to  resist  the  steam -pressure  without  springing, 
the  larger  diameter  would  wear  sufficiently  away  to  cause 
the  valve  to  leak ;  whereas,  if  the  disc  were  made  suffi- 
ciently thin  to  enable  it  to  spring  easily,  the  outer  diametei 
would  wear  to  almost  a  feather-edge,  while  the  metal  about 
the  centre  would  nearly  maintain  its  original  thickness. 

It  is  this  inequality  of  wear  in  revolving,  or  side,  or  disc 

surfaces  that  is  Irn  stumbling-block  to  the  success  of  rotary 

engines,  nor  has  there  as  yet  been  suggested  any  method  of 

overcoming  or  compensating  for  it.     It  is  difficult,  indeed, 

20 


234  COMPLETE  PRACTICAL  MACHINIST. 

to  perceive  in  what  direction  such  a  remedy  can  lay,  unless 
it  be  in  making  the  disc  of  hardened  steel  and  tempering 
it,  so  that  being  at  the  outer  diameter  as  hard  as  fire  and 
water  will  make  it,  it  is  so  tempered  that  it  shall  be  gradu- 
ally softer  as  the  diameter  decreases,  until  at  the  centre 
it  is  quite  soft.  Thus  the  degree  of  hardness  of  the 
metal  will  be  as  far  as  possible  in  proportion  to  its  liability 
to  wear. 

In  an  experiment  made  by  me,  I  revolved  two  cast-iron 
disc-surfaces,  of  three  inches  diameter,  under  a  pressure  of 
steam  of  20,  35,  and  70  Ibs.  alternately,  per  square  inch, 
the  surface  being  pressed  together  under  a  pressure  of 
about  7  Ibs.  per  square  inch,  and  the  discs  making  three 
thousand  revolutions  per  minute.  I  found  that,  in  conse- 
quence of  the  light  pressure,  forcing  the  faces  together,  a 
cast-iron  surface  showed  but  very  little  signs  of  wear — not 
sufficient,  indeed,  after  running  ten  hours  a  day  for  ten  days, 
to  efface  the  scraper-marks  from  the  surfaces,  which  had 
become  polished  and  glazed,  as  it  were.  Several  small 
holes  were  then  drilled  in  the  contacting  surfaces,  and 
plugs  of  Babbitt  metal,  brass,  wrought-iron,  and  steel,  were 
inserted,  the  fr.ces  being  rescraped  all  over,  and  the  discs 
then  run  as  before,  the  result  being  that,  after  two  days  of 
running,  the  cast-iron  appeared  smooth  and  bright  as  before, 
while  the  brass,  wrought-iron,  steel,  and  Babbitt  metal  were 
found  to  be  worn  positively  below  the  surface  of  the  cast- 
iron,  several  repetitions  of  the  last  experiment  giving,  in 
each  case,  a  like  result. 

The  reason  that  the  liability  to  cut  is  found  in  practice  to 
be  much  greater  in  revolving  than  in  reciprocating  surfaces 
is  that,  when  a  revolving  surface  commences  to  cut,  the 
particles  of  metal  being  cut  are  forced  into  and  add  them- 
selves, in  a  great  measure,  to  the  particles  performing  the 
cutting,  increasing  its  size  and  the  strain  of  contact  of  the 
surfaces,  causing  them  to  cut  deeper  and  deeper  until  at 
least  an  entire  revolution  has  been  made,  when  the  severed 


DEVOLVING  SURFACES.  235 

particles  of  metal  release  themselves,  ami  are  for  the  most 
part  forced  iiito  the  grooves  made  by  the  cutting. 

In  reciprocating  surfaces,  when  any  part  commences  to 
cut,  the  edge  of  the  protruding  cutting  part  is  abraded  by 
the  return  stroke,  which  fact  is  clearly  demonstrated  in 
either  fitting  or  grinding  in  the  plugs  of  cocks,  in  which 
operation  it  is  found  absolutely  necessary  to  revolve  the 
plugs  back  and  forth,  to  prevent  the  cutting  which  inevita- 
bly and  invariably  takes  place  if  the  plug  is  revolved  in  a 
continuous  direction.  Furthermore,  when  a  surface  revolves 
in  a  continuous  direction,  any  grit  that  may  lodge  in  a  speck, 
hollow  spot,  or  soft  place  in  the  metal,  will  cut  a  groove 
and  not  easily  work  its  way  out,  as  is  demonstrated  in 
polishing  work  in  a  lathe ;  for  be  the  polishing  material  as 
fine  as  it  may,  it  will  not  polish  so  smoothly  unless  kept  in 
rapid  motion  back  and  forth.  Grain  emery  used  upon  a 
side-face,  such  as  tho  outer  face  of  a  cylinder-cover,  will 
lodge  in  any  small,  hollow  spots  in  the  metal  and  cut 
grooves,  unless  the  polishing  stick  be  moved  rapidly  back 
and  forth  between  the  centre  and  the  outer  diameter.  If  a 
revolving  surface  abrades  so  much  as  to  seize  and  come  to 
a  standstill,  it  will  be  found  very  difficult  to  force  it  for- 
ward, while  it  will  be  comparatively  easy  to  move  it  back- 
ward, which  will  not  only  release  the  particles  of  metal 
already  severed  from  the  main  body,  and  permit  them  te 
lodge  in  the  grooves  due  to  the  cutting,  but  will  also  dislodge 
the  projecting  particles  which  are  performing  the  cutting, 
so  that  a  few  reciprocating  movements  and  ample  lubrica- 
tion will,  in  most  cases,  stop  the  cutting  and  wash  out  the 
particles  already  cut  from  the  surfaces  of  the  metal. 

It  is  held  by  many  that  fast-running  bearings  filled  with 
Babbitt  metal  will  wear  better  than  brass  bearings.  Such, 
however,  is  not  the  case,  if  the  bearings  are  properly  fitted  ; 
the  only  advantage  possessed  by  Babbitt  metal  bearings  is 
that  they  are  more  easily  fitted  ;  because  the  Babbitt  will 
run  so  as  to  make  an  even  and  equal  bearing  upon  the 


<J36  COMPLETE  PRACTICAL  MACHINIST. 

shaft,  and  it  is  therefore  only  necessary  to  set  the  shaft  true 
before  pouring  the  metal,  to  insure  an  even  and  true  bear- 
ing ;  whereas,  after  the  brasses  are  fitted  and  bored,  they 
require  fitting  to  the  shaft  while  in  their  places,  and  this 
being  a  somewhat  tedious  operation  is  often  omitted,  the 
consequence  being  that  the  journal  does  not  bed  fairly  on 
the  bearing  surface,  and  thus  the  whole  strain  of  the  bear- 
ing is  placed  upon  the  reduced  surface  of  the  brasses  which 
beds  upon  the  journals,  and  the  increase  of  journal -pressure 
per  inch,  placed  upon  the  brass,  induces  undue  abrasion, 
and  a  consequent  rough  surface  tending  to  produce  con- 
tinuous abrasion  and  heating.  In  bearings  of  this  kind, 
the  boxes  or  bearings  should  be  of  hard  composition,  as, 
say,  a  mixture  of  12  parts  of  copper  to  H  of  tin,  and  J  of 
zinc,  which  will  turn  in  the  lathe  easily,  and  yet  be  suffi- 
ciently hard  to  resist  abrasion  under  ordinary  dufy. 

ANNEALING   OR   SOFTENING. 

To  soften  finished  iron  or  steel  work  without  damaging 
its  finish,  well  lute  an  iron  box  with  fire-clay,  and  place 
the  work  in  it,  surrounded  by  turnings  or  borings  of  the 
same  metal  as  itself.  Fill  the  box  full  of  such  turnings, 
place  the  lid  on,  and  lute  it  with  fire-clay ;  then  place  it 
in  a  furnace,  heat  slowly  to  a  red  heat,  and  allow  the  fur- 
nace fire  to  go  out  and  the  box  to  cool  in  the  furnace. 

To  anneal  electro-magnets,  first  heat  the  iron  to  a  very 
low  red  heat,  and  let  it  cool  off  in  soft  soap ;  then  reheat 
to  a  low  red,  and  let  it  cool  while  well  covered  in  slaked 
lime. 

To  anneal  ordinary  steel,  heat  it  to  a  low  red  heat  and 
allow  it  to  cool  in  ashes  or  lime. 

To  remove  the  sand  and  scale  from  iron  castings, 
immerse  them  in  a  pickle  composed  of  one  part  oil  of 
vitriol  to  three  parts  of  water.  In  six  to  ten  hours  remove 
and  wash  them  with  clean  water ;  when  time  is  no  object, 
make  the  solution  weaker,  and  let  them  pickle  longer. 


MIXTURE   OF  METALS.  237 

MIXTURES   OF   METALS. 

Babbitt  metal  bearings  for  fast  running  journals — Tin,  50 
parts ;  antimony,  5  parts  ;  copper,  1£  parts. 

Brass  for  journal  boxes — Copper,  10  pounds;  tin,  1J 
pounds ;  spelter,  2  pound. 

Brass  for  valves — Copper,  9  pounds ;  tin,  1  pound ;  spelter, 
i  pound. 

Bell  metal — Copper,  50  pounds  ;  tin,  11  pounds. 

Yellow  brass  —  Copper,  20;  zinc,  10  pounds;  lead, 
3  pound. 

Yellow  brass  for  castings — Copper,  36  parts ;  zinc,  17 
parts ;  lead,  21  parts;  tin,  2]  parts.  The  zinc  to  be  added 
last  to  prevent  its  burning  away. 

Gun  metal — Copper,  9  parts ;  tin,  1  part./ 

Solders— Fine,  tin  1  part,  lead  1  part.  Plumbers,  tin  1 
part,  lead  2  parts.  For  cast-iron,  tin  2  parts,  lead  1  part. 

Soldering  liquid  —  Muriatic  acid  which  has  dissolved 
scraps  of  zinc  until  sponge  zinc  will  form  in  it,  is  fit  for 
soldering  brass  or  copper  work ;  for  cast  or  wrought-iron 
work,  sal-ammoniac  should  be  added  ;  while  for  tin,  the 
latter  may  be  omitted,  and  water,  in  the  proportion  of  one- 
third,  added. 


CHAPTER    XIII. 

TAPS   AND   DIES. 

TAPS  should  be  forged  of  hammered  square  bar  steel, 
and  forged  to  as  near  the  finished  size  as  possible  (so  that 
they  are  large  enough  to  true  up),  because  the  metal  on  the 
outer  surface  of  a  forging  is,  from  receiving  the  most  of  the 
effects  of  the  forging,  of  finer  quality  than  the  interior  metal. 
After  the  forging  of  the  tap  is  complete,  it  should  be  heated 
to  a  low  red  heat  and  covered  in  lime  or  ashes,  the  object 
being  not  only  to  soften  the  metal  and  make  it  easier  to  cut, 
but  to  release  any  tension  there  may  be  upon  the  outer  skin, 
in  consequence  of  the  forging,  for  there  is  a  tension  upon 
the  surface  of  all  forged  as  well  as  cast  work. 

The  effect  of  blows  delivered  upon  forged  work  by  the 
blacksmith's  tools  is  not  only  greater  upon  the  exterior 
than  upon  the  interior  of  the  metal,  but  is  greatest  upon 
that  part  of  the  forging  which  receives  the  most  working, 
and  upon  that  part  which  is  at  the  lowest  temperature 
during  the  finishing  process :  because  the  blows  delivered 
during  the  finishing  process  are  lighter  than  those  during 
the  earlier  stages  of  the  forging,  and  hence  their  effects  do 
not  penetrate  so  deeply  into  the  body  of  the  metal.  Then 
again,  on  that  part  of  the  metal  which  is  coolest,  the  effects 
of  the  light  hammering  do  not  penetrate  so  deeply ;  and 
from  these  combined  causes,  the  tension  is  not  equally  dis- 
tributed over  the  whole  surface  of  the  forging,  and  hence 
its  removal,  by  cutting  away  the  outer  surface  of  any  one 
part,  and  thus  releasing  the  tension  of  that  part,  alters  the 
form  of  the  whole  body,  which  does  not,  therefore,  assume 
its  normal  shape  until  the  outer  skin  of  its  whole  surface 
238 


TAPS  AND  DIES.  239 

has  been  removed.  While  the  metal  is  at  about  an  even 
heat  all  over,  and  is  above  a  red  heat,  the  effect  of  working 
the  metal  by  forging  it  is  simply,  as  already  stated,  to  im- 
prove its  texture,  to  close  the  grain,  and  thus  to  better  its 
quality,  especially  toward  and  at  its  outer  surface  ;  but  as 
the  tension  commences,  while  and  after  the  metal  loses  its 
redness,  we  adopt  the  plan,  after  forging,  to  heat  the  tap 
all  over  to  a  low  red  heat,  and  to  then  lightly  file  its 
surface  so  as  to  remove  any  protruding  scale ;  then  allow  it 
to  cool  of  itself,  without  any  forging  being  performed  upon 
it  at  that  heat.  This  process  will  nearly,  if  not  entirely, 
remove  the  tension  created  by  the  forging. 
•  If  the  tap  is  a  long  one,  many  experienced  blacksmiths 
state  that  it  should,  after  the  forging  is  completed  and  the 
tap  is  very  nearly  or  quite  cold,  be  stood  endwise  on  the 
anvil,  and  placing  a  flatter  on  the  end  of  the  tap,  sirike  the 
flatter  a  sharp  blow  with  a  light  sledge,  which  it  is  stated 
will  set  the  metal  so  that  it  will  not  warp  in  the  process  of 
hardening.  An  excellent  plan  to  effect  the  same  object  is 
to  rough  out  the  tap  all  over,  so  as  to  remove  the  tension, 
and  to  then  heat  the  tap  to  a  law  red,  and  allow  it  to  cool 
gradually. 

The  threads  of  taps  of  the  smaller  sizes  should  be  finished 
by  a  chaser,  so  as  to  insure  correctness  in  the  angles  and 
in  the  depth  of  the  thread. 

The  taper  tap  should  not  be  given  more  taper  than  the 
depth  of  the  thread  in  the  length  of  the  tap,  or  it  is  liable 
to  be  used  on  holes  that  are  too  small,  which  places  more 
duty  upon  it  than  is  necessary  and  than  it  should  be 
required  to  perform  ;  rendering  it,  in  consequence,  liable  to 
break  from  the  excessive  strain,  and  causing  the  square 
end  of  the  tap,  where  the  wrench  fits,  to  twist  and  the 
corners  to  become  rounded. 

A  tap  which  has  much  clearance  placed  upon  its  thread, 
by  the  screw-cutting  tool,  or  by  a  chaser,  will  cut  very 
freely,  and  \\  ill  answer  for  rough  work ;  but  such  a 


210  COMPLETE  PRACTICAL.  MACHINIST. 

tap  does  not  cut  a  really  good  thread,  and  generally 
„.  leaves  the  diameter  of  the  thread  in  the  hole 

'  larger  than  tlie  diameter  of  the  tap  itself,  because 
the  tap  is  liable  to  wabble,  and  the  least  excess 
of  pressure,  on  one  end  of  the  tap  wrench  more 
than  on  the  other,  causes  the  tap  to  lean  towards 
the  end  of  the  wrench  receiving  the  most  press- 
ure,  and  hence,  to  tap  a  hole  larger  than  itself. 
Especially  is  this  liable  to  occur  if  the  tap  wrench 
has  more  than  one  square  hole  in  it  so  as  to  enable 
the  eame  wrench  to  be  used  on  more  than  one  size 
of  tap ;  for  in  such  a  case,  the  holes  being  not 
in  the  centre  of  the  wrench,  the -weight  of  the 
wrench  and  the  pressure  placed  011  the  end  of  the 
wrench  will  exert  more  pressure  on  one  side  of  the 
tap  than  the  other,  in  consequence  of  their 
greater  distance  or  longer  leverage  from  the  tap. 
The  same  effects  (from  the  use  of  such  wrenches) 
are  experienced  in  using  taps  having  no  clear- 
ance in  the  thread  ;  but  the  thread  in  this  latter 
case  is  so  much  nearer  a  fit  to  the  hole  that  it 
serves  as  a  guide  and  keeps  the  tap  steady. 

Then,  again,  if  a  tap  has  much  clearance  upon 
the  thread,  and  is  required  to  back  out  from  and 
tiot  pass  entirely  through  tlfc  thread,  the  cuttings 
jam  between  the  thread  in  the  hole  and  the  thread 
upon  the  tap,  especially  if  the  hole  is  in  cast-iron. 
The  sides  of  the  teeth  of  such  a  tap  have  a  very 
small  bearing  upon  the  sides  of  the  thread  in  the 
hole,  caueing  the  tap,  if  used  by  hand,  to  work 
very  unsteadily. 

Taps  for  use  in  machines,  such  as  the  nut  tap 
shown  in  Fig.  192,  which  are  intended  to  pass 
through  the  work,  may  have  considerable  clear- 
ance in  the  thread,  the  greater  part  of  which 
clearance  should  be  at  the  back  end  of  the  teeth. 


TAPS  AW)  -DIES.  -»;^T  24b 

Taps  for  ordinary -work 'may  have  a  very  slight  amount 
of  clearance  placed  upon  the  teeth  back  from  the  cutting 
edge,  just  sufficient  in  fact  to  prevent  them  from  binding 
hard  against  the  sides  of  the^  thread  being  cut,  and  y^-not 
sufficient  to  prevent  the  sides  of  the  teeth  from  acting  as  a 
guide  to  steady  the  tap -in  the  hole. being  threaded  or 
tapped.  Taps  for  holes  requiring  .to  be  unusually  exaetrin 
their  diameter  should  not  have  any  clearance  placed  .upon 
the  sides  of  the  thread,  but  may  have  a  flat  place ^  filed 
along  the  tops  of  each  row  of  teeth,  the  flat  face,  termi- 
nating close  to  the  flute  on  either  side  of  the  length  of  the 
teeth,  but  in  no  case  extending  entirely  to  the  flute.  The 
flute  of  a  tap  should  be  volute  and  not  carried  over  the 
back  end  of  the  teeth,  otherwise  the  cuttings  are  apt- to 
jam  when  the  tap  is  being  backed  out. 

If  the  flute  of  a  tap  is  made  spiral,  it  serves  to  steady  the 
tap  in  the  hole,  especially  if  the  latter  is  not  round ;  but  the 
extra  trouble  involved  in  making  spiral  flutes  lias  pre- 
vented their  universal  application. 

The  taps  shown  in  Fig.  193  represent  a  form  of  tap  not 

^7.193.. 


TAPER. 


PLUG. 


infrequently  made,  but  which  is  wrong,  because  of  having 
taper  in  the  diameter  of  the  bottom  of.  the  thread. 

The  taper  of  a  hand  or  machine-tap,  for  all  save  gas 
21 


242  COMPLETE  PRACTICAL  MACHINIST. 

taps,  should  be  turned  parallel  the  same  as  a  plug  tap,  and 
then  have  the  taper  made  by  turning  off  the  thread  to  a 
straight  taper  which  just  turns  the  thread  out  at  the  enter- 
ing end  of  the  tap,  and  leaves  about  four  lull  threads  at 
the  end  of  the  tap  thread ;  and  such  a  tap  will  work  much 
more  steadily  than  one  having  more  thread  on  the  taper  end. 

Taps  having  thread  on  the  small  end  of  the  taper  tap  do 
not  cut  a  correct  angle  of  thread  at  starting,  and  gradu- 
ally right  themselves  as  the  tap  enters,  the  reason  for 
which  will  be  found  illustrated  in  Fig.  205,  and  in  the 
remarks  upon  adjustable  screw  dies. 

The  plain  part  of  a  tap,  that  is,  that  part  from  the  thread 
to  the  end  of  the  square  where  the  wrench  fits,  should  be 
turned  down  a  little  smaller  in  diameter  than  the  bottom 
of  the  thread  (unless  in  the  case  of  very  small  taps),  so 
that  the  tap  can  pass  right  through  the  hole  in  all  cases 
where  the  hole  passes  through  the  work,  thus  saving  time 
by  obviating  the  necessity  of  winding  the  tap  back,  and 
furthermore  preserving  the  cutting  edges  of  the  tap  teeth 
by  avoiding  the  abrasion  caused  by  their  being  rubbed 
backwards  against  the  metal  of  the  hole.  For  special  work, 
where  the  holes  to  be  tapped  do  not  pass  through  the  work, 
and  it  is  therefore  compulsory  to  wind  the  tap  backwards 
to  take  it  out  of  the  hole,  the  plain  part  of  the  tap  may  be 
left  larger  than  the  diameter  of  the  thread,  the  advantage 
being  that  the  squares  of  several  different  sizes  of  taps  may 
be  made  alike,  and  therefore  to  suit  one  tap  wrench. 

Taps  for  use  in  holes  to  be  tapped  deeply  should  be  made 
slightly  larger  in  diameter  than  those  used  to  tap  shallow 
ones,  because  in  deep  holes  the  tap  is  held  steady  by  its 
depth  in  the  hole,  and  because  whatever  variation  there 
may  be  in  the  pitch  of  the  threads  in  the  hole  and  those  on 
the  bolt,  is,  of  course,  experienced  to  an  extent  greater  as 
the  length  of  the  thread  (that  is,  the  number  of  threads) 
increases. 

It  is  an  excellent  plan  to  finish  the  threads  of  a  tap  by 


TAPS  AND  DIES.  243 

passing  it  through  a  sizing  die,  that  is,  a  solid  die  kept  for 
that  special  purpose ;  but  very  little  metal  must  be  left  on 
the  tap  for  the  solid  die  to  take  off,  or  it  will  soon  wear  and 
get  larger.  In  making  such  a  solid  die,  let  its  thickness  be 
rather  more  than  the  diameter  of  the  tap  it  is  intended  to 
cut,  and  make  allowance  for  its  shrinkage  in  hardening, 
for  all  holes  shrink  in  hardening,  while  taps  swell  or  become 
larger  from  that  process ;  an  allowance  for  this  must  therefore 
be  made  both  in  the  case  of  the  tap  and  the  die.  In  the  case 
of  the  solid  die,  it  will  be  found  that  not  only  does  the  hole 
become  smaller,  but  the  external  dimensions  of  the  entire 
die  have  become  larger  by  reason  of  the  hardening,  so  that 
while  the  term  shrinkage  is  correct,  as  applied  to  the  hole, 
it  is  incorrect  as  applied  to  the  die,  the  fact  being  that  the 
metal  of  the  die  (the  same  as  the  metal  of  the  tap)  has 
expanded,  extending  its  dimensions  in  all  directions,  and 
therefore  in  the  direction  of  the  centre  of  the  hole,  hence 
causing  a  decrease  in  its  diameter  or  bore. 

Three  flutes  are  all  that  are  necessary  to  small  taps 
(that  is,  those  up  to  about  half  an  inch  in  diameter),  which 
leave  the  tap  stronger  and  less  liable  to  wabble,  especially 
in  holes  that  are  not  round,  than  if  it  had  four  flutes. 
Taps  of  a  larger  size  may  have  more  flutes,  but  the  num- 
ber should  always  be  an  odd  one,  so  that  the  tap  will  do 
its  work  steadily. 

The  United  States  standard  for  threads,  which  was  first 
adopted  by  the  Franklin  Institute,  is  as  follows : 

DIAMETER   OF   TAP. 


i  i|i|H|ii|if|uiii:u|i||  2 


NUMBER   OF    THREADS   TO    INCH. 


20l8  16  1413121110    9     8     7     7     6     6    5      5     5 


In  this   standard,  the  screw  threads   are  formed  with 
straight  sides  at  an  angle  of  sixty  degrees  to  each  other, 


244  COMPLETE  PRACTICAL  MACHINIST. 

having  a  flat  surface  at  the  top  and  bottom  equal  to  one- 
eighth  of  the  pitch,  the  pitches  as  above. 

The  English  or  Whitworth  standard  varies  from  the 
above  both  in  shape  and  number  of  threads  to  inch,  as 
below : 

DIAMETER    OF    TAP. 


1  6 


NUMBER    OF    THREADS   TO    INCH. 


20  1 18 1 16   14 1 12 ; 11 1 10    9     8     7  |  7     6  1  6 


In  this  standard,  the  screw  threads  are  formed  with  flat 
sides  at  an  angle  of  fifty-five  degrees  to  each  other,  with  a 
rounded  top  and  bottom.  The  proportions  for  the  rounded 
top  and  bottom  are  obtained  by  dividing  the  depth  of  a 
sharp  thread  having  sides  at  an  angle  of  fifty-five  degrees, 
into  six  equal  parts,  and  within  the  lines  formed  by  the 
sides  of  the  thread,  and  the  top  and  bottom  dividing  lines 
inscribing  a  circle,  which  determines  the  form  of  top  and 
bottom  of  thread. 

Taps  should  be  heated,  for  hardening,  in  a  charcoal  fire, 
and  be  heated  slowly  to  a  cherry  red,  and  then  dipped  per- 
pendicularly into  clean  water.  The  water  should  be  made 
sufficiently  warm  to  feel  pleasant  to  the  hand ;  for,  if  the 
water  has  not  the  cold  chill  taken  off  it,  the  taps  are  apt  to 
crack  along  the  flutes.  The  tap  should  be  lowered  per- 
pendicularly in  the  water,  even  after  it  has  disappeared 
below  the  surface ;  but  in  no  case  should  it  be  moved  side- 
ways, or  it  will  warp.  It  should  not  be  taken  out  of  the 
water  until  quite  cold,  or  it  will  crack  after  it  is  taken  from 
the  water  and  during  the  cooling  process.  After  the  tap  is 
hardened,  it  should  be  brightened  along  the  flutes  and  on 
the  plain  part,  and  then  lowered,  as  follows :  A  piece  of 
tube,  about  half  the  length  of  the  tap,  and  of  about  twice 
or  three  times  its  diameter,  and  having  its  thickness  about 
the  same,  if  possible,  as  the  diameter  of  the  tap,  should  be 


TAPS  AND  DIES.  245 

heated  in  the  fire  to  an  even  cherry-red  heat,  and  then 
taken  from  the  fire  and  placed  in  such  a  position  that  it  is 
open  to  clear  daylight  and  not  affected  by  the  rays  of  light 
from  the  fire. 

The  tap  should  be  held  in  a  pair  of  tongs,  whose  jaws 
have  been  well  warmed ;  and  a  small  piece  of  metal  should 
be  interposed  between  the  jaws  of  the  tongs  and  the  sides- 
of  the  square  of  the  wrench-end  of  the  tap,  so  that  the  tongs 
may  not  obstruct  the  square  of  the  tap  from  receiving  the 
heat  from  the  tube.  The  tap  and  tongs  should  then  be 
passed  through  the  heated  tube,  so  that  the  square  end  of 
the  tap  and  the  tongs  only  will  be  inside  the  tube.  The  tap 
should  be  slowly  revolved  while  in  this  position ;  and  when 
the  tap  has  at  that  end  become  slightly  heated,  but  not 
enough  to  draw  the  color,  the  shank  and  threaded  part  of 
the  tap  should  then  be  slowly  passed  endways  back  and 
forth,  and,  while  slowly  revolving  through  and  through  the 
centre  of  the  tube,  until  the  color  appears,  and  if  it  appears 
of  an  even  hue  all  over,  proceed  until  a  brown  color  appears ; 
then  withdraw  the  tap  from  the  tube  and  quench  it  perpen- 
dicularly in  warm  water.  If,  howrever,  the  color  does  not 
not  appear  so  quickly  in  any  particular  part,  hold  that  part 
in  the  tube  a  little  the  longest,  and  if  either  end  lowers  too 
rapidly,  cool  it  by  a  slight  application  of  oil.  The  square 
end  of  the  tap,  on  which  the  wrench  fits,  may  be  lowered 
to  a  deeper  color,  as  may  also  the  shank  of  the  tap,  than 
the  threaded  part,  which  will  leave  them  stronger  and  less 
liable  to  twist  or  break.  By  using  the  size  of  tube  here 
recommended,  it  will  be  found  that  the  tempering  process 
will  be  performed,  and  the  colors  appear  very  slowly,  so 
that  there  will  be  ample  time  to  judge  when  the  precise 
requisite  degree  of  hardness  has  been  reached.  This  plan 
is  far  superior  to  tempering  in  heated  sand.  Very  long  taps 
may  be  greased  and  heated  preparatory  to  being  hardened 
in  molten  lead,  the  object  being  to  heat  the  outside  of  the 
tap  evenly  all  over  to  a  red  heat  so  rapidly  that  the  inside 
21 


246  COMPLETE  PRACTICAL  MACHINIST. 

metal  of  the  tap  is  comparatively  cool,  hence,  when  the  tap 
is  hardened,  the  outside  only  is  hardened  ;  and,  if  the  tap 
warps  in  the  hardening,  it  can,  after  being  tempered,  be 

Fig.  194. 


straightened,  the  soft  metal  of  the  centre  of  tap  preventing 
it  from  breaking  in  the  straightening,  which  should  be  per- 

Fig.  195. 


formed  with  a  leaden  hammer,  and  with  the  tap  resting 
upon  lead. 

In  the  Whit  worth  or  English  standard,  taps  are  given 


TAPS  AND  DIES. 


247 


three  flutes,  which  has  the  merit  that  the  thread  will  be 
cut  more  nearly  axially  true  with  the  hole,  notwithstand- 
ing that  the  hole  may  be  out  of  round,  or  have  a  blow 
hole  on  one  side. 

Thus  in  Fig.  195  we  have  a  three-flute  tap  iu  a  hole 
out  of  round  at  A,  and  it  is  obvious  that  when  a  cutting 
edge  meets  the  recess  at  A,  all  three  teeth  will  cease  to 
cut ;  hence  there  will  be  no  inducement  for  the  tap  to 
move  over  toward  A.  But  in  the  case  of  the  four-flute 
tap  in  Fig.  194,  when  the  teeth  come  to  A  there  will  be  a 
strain  tending  to  force  the  teeth  over  toward  the  depres- 


Fig.  196. 


sion  A.  How  much  a  given  tap  would  actually  move 
over  would,  of  course,  depend  upon  the  amount  of  clear- 
ance ;  but  whether  the  tap  has  clearance  or  not,  the  three- 
flute  tap  will  not  move  over,  while  with  four  flutes  the  tap 
would  certainly  do  so.  Again,  with  an  equal  width  of 
flute  there  is  more  of  the  circumference  tending  to  guide 
and  steady  the  three-flute  and  the  four-flute  tap.  If  the 
hole  has  a  projection  instead  of  a  depression,  as  at  B, 
Figs.  196  and  197,  then  the  advantage  still  remains  with 
the  three-flute  tap,  because  in  the  case  of  the  three  flutes, 
any  lateral  movement  of  the  tap  will  be  resisted  at  the 


248  COMPLETE  PRACTICAL  MACHINIST. 

two  points  C  and  D,  Neither  of  which  are  directly  oppo- 
site to  the  location  of  the  projection  B;  hence,  if  the  pro- 
jection caused  the  tap  to  move  laterally,  say,  T^ff  inch, 
the  effect  at  C  and  D  would  be  very  small,  whereas  in  the 
four-flute,  Fig.  197,  the  effect  at  E  would  be  equal  to  the 
full  amount  of  lateral  motion  of  the  tap. 

It  is  quite  true  that  the  four  teeth  will  cut  easier  than 
the  three,  but  against  this  we  have  the  fact  that  the  three 
will  tap  a  more  parallel  hole  because  it  will  work  steadier. 
The  length  of  the  teeth  .and  the  width  of  flute  would  obvious- 
ly influence  the  steadiness  of  the  tap,  especially  if  its  teeth 


Fig.  197. 


are  a  true  circle,  and  therefore  have  no  clearance.  In 
Whitworth's  taps  the  flutes  are  narrower,  and  the  teeth 
longer  than  in  American  practice,  producing  more  parallel 
and  round  holes,  but  requiring  more  power  to  operate 
them.  Fig.  198  represents  the  Whitworth  form.  Fig.  199 
the  Brown  &  Sharpe,  and  Fig.  200  the  Pratt  &  Whitney 
for  hand  taps;  average  American  practice  being  repre- 
sented in  Fig.  201.  The  Brown  &  Sharpe,  it  will  be  ob- 
served, has  the  shortest  teeth  and  the  most  shallow  flute, 
and  is  the  strongest. 

In  hand  taps  the  position  of  the  square  with  relation  to 


TAPS  AND  DIES. 


249 


the  cutting-edges  is  of  consequence;   thus,  in  Fig.  202, 
there  being  a  cutting-edge,  A,  opposite  to  the  handle,  any 

Fig.  198.  Fig.  199. 


Fig.  200. 


Fig.  202. 


Fig.  203. 


undue  pressure  on  that  end  of  the  handle  would  cause  A 
to  cut  too  freely  and  the  tap  to  enlarge  the  hole;  whereas 


250 


COMPLETE  PRACTICAL  MACHINIST. 


in    Fig.   203  this   tendency  would  be  greatly  removed, 
and  still  more  removed  in  Fig.  204,  the  disadvantage  of 


Fig.  204. 


that  in  Fig.  202  being  greatest  when  a  single-ended 
wrench  is  used. 

ADJUSTABLE    DIES, 

That  is,  ihose  which  take  more  than  one  cut  to  make  a  full 
thread,  should  never  be  used  in  cases  where  a  solid  die  will 
answer  the  purpose,  because  adjustable  dies  take  every  cut 
at  a  different  angle  to  the  centre  line  of  the  bolt,  as 
explained  by  Figs.  205  and  206. 

Fig.  205  represents  an  ordinary  screw.  It  is  evident  that 
the  pitch  from  a  to  B  is  the  same 
as  from  C  to  D.  Let  a  b,  in  Fig. 
206,  represent  the  centre-line  of 
the  bolt  lengthwise, and  cda,  line 
at  right  angles  to  it :  then  let  from 
the  point  e  to  the  point  /  repre- 
sent the  circumference  of  the  top 
of  the  thread,  and  from  e  to  g  the 
circumference  of  the  bottom  of  the  thread,  the  lines  h  h  rep- 
resenting their  respective  pitches;  and  we  have  the  line  k, 
as  representing  the  angle  of  the  top  of  the  thread  to  the 
centre  line  a  6,  of  the  bolt,  and  the  line  /,  as  representing  the 
angle  of  the  bottom  of  the  thread  to  the  centre-line  a  b,  of 
the  bolt,  from  which  it  becomes  apparent  that  the  top  and 
the  bottom  of  the  thread  are  at  different  angles  to  the 
centre  line  of  the  bolt. 


TAJ'S  AND  DIES. 


251 


The  tops  of  the  teeth  of  adjustable  dies  are  themselves  at 
the  greatest  angle,  while  they  commence  to  cut  the  thread 
ou  the  bolt  at  its  largest  diameter,  where  it  possesses  the 


Fig.  206. 


least  angle,  so  that  the  dies  cut  a  wrong  angle  at  first,  and 
gradually  approach  the  correct  angle  as  they  cut  the  depth 
of  the  thread. 

From  what  has  been  already  said,  it  will  be  perceived 
that  the  angle  of  thread,  cut  by  the  first  cuts  taken  by 
adjustable  dies,  is  neither  that  of  the  teeth  of  the  dies  nor 
that  required  by  the  bolt,  so  that  the  dies  cannot  cut  clean 
because  the  teeth  do  not  fit  the  grooves  they  cut,  and  drag 
in  consequence. 

DIES   FOR   USE  IN   HAND  STOCKS 

are  cut  from  hubs  of  a  larger  diameter  than  the  size  of  bolt 
the  dies  are  intended  to  cut ;  this  being  done  to  cause  the 
dies  to  cut  at  the  cutting  edges  of  the  teeth  which  are  at  or 
near  the  centre  of  each  die,  so  that  the  threads  on  each 
side  of  each  die  act  as  guides  to  steady  the  dies,  and  pre- 
vent them  from  wabbling  as  they  otherwise  would  do ;  the 
result  of  this  is,  that  the  angle  in  the  thread  in  the 
dies  is  not  the  correct  angle  for  the  thread  of  the  bolt,  even 
when  the  dies  are  the  closest  together,  and  hence  taking 
the  finishing  cuts  on  the  thread,  although  the  dies  are 


252  COMPLETE  PRACTICAL  MACHINIST. 

nearer  the  correct  angle  when  in  that  position  than  in  any 
other.  A  very  little  practice  at  cutting  threads  with 
stocks  and  dies  will  demonstrate  that  the  tops  of  the 
threads  on  a  bolt,  cut  by  them,  are  larger  than  was  the 
diameter  of  the  bolt,  before  the  thread  was  commenced  to 
be  cut,  which  arises  from  the  pressure,  placed  on  the  sides 
of  the  thread  of  the  bolt,  by  the  sides  of  the  thread  on  the 
dies,  in  consequence  of  the  difference  in  their  angles; 
which  pressure  compresses  the  sides  of  the  bolt  thread  (the 
metal  being  softer  than  that  of  the  dies)  and  causes  a  cor- 
responding increase  in  its  diameter.  It  is  in  consequence 
of  the  variation  of  angle  in  adjustable  dies  that  a  square 
thread  cannot  be  cut  by  them,  and  that  they  do  not  cut  a 
good  V  thread. 

In  the  case  of  a  solid  die,  the  teeth  or  threads  are  cut  by 
a  hub  the  correct  size,  and  they  therefore  stand  at  the 
proper  angle ;  furthermore,  each  diameter  in  the  depth  of 
the  teeth  of  the  die  cuts  the  corresponding  diameter  on  the 
bolt,  so  that  there  is  no  strain  upon  the  sides  of  the  thread 
save  that  due  to  the  force  necessary  to  cut  the  metal  of  the 
bolt  thread. 

In  a  taper  tap,  whether  it  have  a  V  thread  or  a  square 
one,  each  individual  diameter  and  angle  of  thread  cuts  the 
same  diameter  and  angle  in  the  hole,  providing  the  bottom 
of  the  thread  is  of  the  same  diameter  all  along  the  tap, 
and  that  the  taper  is  made  by  turning  off  the  tops  of  the 
threads ;  if,  however,  the  tap  is  made  taper  and  the  thread 
is  cut  taper,  the  angles  of  the  sides  of  the  thread  itself  will 
not  stand  true  with  the  diameter  of  the  body  of  the  bolt  or 
tap,  nor  will  the  angle  of  the  thread  stand  true  with  the 
centre  line  of  the  length  of  the  bolt. 

A  solid  die,  having  the  teeth  tapered  off  so  that  at  the 
entrance  there  will  be  the  bottom  of  the  thread  only  and  a 
full  thread  will  not  have  been  reached  until  the  bolt  has 
entered  the  die  to  a  distance  equal  to  five  or  six  times 
the  amount  of  the  pitch  of  the  thread,  will  cut  a  moder- 


TAPS  AND  DIES.  253 

ately  good  square  thread,  but  such  dies  take  a  great  deal 
of  power  to  drive  them. 

In  making  dies,  whether  they  are  adjustable  or  not,  it 
is  of  the  utmost  importance  that  the  recesses,  or  spaces  cut 
to  form  the  cutting  edge  of  the  teeth,  be  roomy,  so  that 
the  cuttings  will  pass  easily  away  and  not  clog  in  the  die, 
as  is  too  commonly  the  case.  The  teeth  of  a  die  may  be 
given  a  little  top  rake. 

Fig.  207  represents  a  pair  of  stocks  and  dies  of  the  pat- 
tern in  ordinary  use,  there  being  to  each  pair  of  stock 
dies  from  i  to  \,  inclusive,  by  32ds.  Similar  stocks 

Fig.  207. 


with  keys  instead  of  pins,  and  containing  dies  up  to  1J 
inches,  are  supplied  by  the  same  firm. 

In  the  Whitworth  stocks  and  dies  there  are  two  cutting 
dies  or  chasers  and  one  guide  die,  the  construction  being 
as  follows. 

In  Fig.  208,  A  is  the  guide  die,  and  B  C  are  the 
chasers,  which  are  set  in  to  the  cut  by  a  key  having 
bevels  at  a  P.  The  two  chasers  B  and  0  are  moved  by 
the  key  in  lines  that  would  meet  at  D,  and,  therefore,  at 
a  point  that  is  behind  the  centre  of  the  work,  and  this  has 
the  effect  of  preserving  their  clearance.  It  is  obvious, 
for  example,  that  as  these  chasers  cut  a  thread  on  the 
work  the  latter  will  move  over  in  the  dies  toward  chaser 
A  on  account  of  the  thread  on  the  work  sinking  into  the 
threads  on  A,  and  this  motion  would  prevent  the  chasers 
B  C  from  cutting  if  they  moved  in  a  line  pointing  to  the 
centre  of  the  work.  This  is  more  clearly  shown  in  Fig. 
22 


254 


COMPLETE  PRACTICAL  MACHINIST. 


209,  in  which  the  guide  die  A  and  one  of  the  cutting  dies 
or  chasers  B  is  shown  removed  from  the  stock,  while  the 


Fig.  208. 


bolt  to  be  threaded  is  shown  in  two  positions — one  when 
the  chaser  B  is  at  the  circumference  of  the  work,  and  the 


TAPS  AND  DIES.  255 

other  when  it  has  entered  to  the  full  thread  depth,  the 
Fig.  209. 


points  or  dots.  E  and  G,  representing  the  respective  centres 
of  the  work  tor  the  two  positions. 


CHAPTER  XIV. 

VISE- WORK — TOOLS. 
CHISELS. 

FLAT  chisels  are  made  from  two  shapes  of  bar  steel,  one 
of  which  is  shown  in  Fig.  210,  and  the  other  in  Fig.  210  a. 

Fig.ZW.  Fig.ZWa. 


The  difference  between  the  two  is,  that  as  the  cutting  edge 
wants  to  be  parallel  to  the  flats  on  the  chisel,  and  as 
Fig.  210  has  the  widest  flat,  it  is  easier  to  tell  when  the 
(256) 


VISE-  WORK— TOOLS. 


257 


Fig.  211. 


cutting  edge  and  the  flat  are  parallel,  and  the  broad  flat 
is  the  best  guide  in  holding  the  chisel  level  with  the  sur- 
face to  be  chipped.  Either  of  these  chisels  is  of  a  proper 
width  for  wrought-iron  or  steel,  because  chisels  used  on 
these  metals  take  all  the  power  to  drive  that  can  be  given 
with  a  hammer  of  the  usual  proportions  for  heavy  chip- 
ping, which  is:  weight  of 
hammer  If  Ibs.,  length  of 
hammer  handle  15  inches, 
the  handle  to  be  held  at  its 
end  and  swung  back  about 
vertically  over  the  shoulder. 
If  we  use  so  narrow  a  chisel 
on  cast-iron  or  brass  and 
give  full-force  hammer- 
blows,  it  will  break  out  the 
metal  instead  of  cutting  it, 
and  the  break  may  come 
below  the  proper  depth  and 
leave  ugly  cavities ;  so  for 
these  metals  the  chisel  may 
be  made  broader,  as  in  Fig. 
211,  so  that  the  force  of  the 
blow  will  be  spread  over  a 
greater  length  of  chisel  edge 
and  will  not  move  forward 
so  much  at  each  blow,  and 
therefore  it  will  not  break 
the  metal  out.  Another  ad- 
vantage is,  that  the  broader  the  chisel  the  easier  it  is  to  hold 
its  edge  fair  with  the  work  surface,  and  make  smooth  chip- 
ping. The  chisel  point  must  be  made  thin  as  possible, 
the  proportions  shown  in  the  figures  being  suitable  for  new 
chisels.  In  grinding  the  two  facets  to  form  the  chisel  we 
must  be  careful  to  avoid  grinding  them  rounded,  as 
shown  in  A  in  the  magnified  chisel  ends  in  Fig.  213,  the 
22* 


258  COMPLETE  PRACTICAL  MACHINIST. 

proper  way  being  to  grind  them  flat  as  at  B  in  the  sketch. 
Fig.  212. 


Fig.  214. 


We  must  make  the  angle  of  these  two  facets  as  acute  as 


VISE-  WORK— TOOLS. 


259 


215. 


possible,  because  the  chisel  will  then  cut  easier.  The 
angle  at  C  in  Fig.  212  is  about  right  for 
brass,  and  that  at  D  is  about  right  for 
steel.  The  difference  is  that  with  hard 
metal  the  more  acute  angle  dulls  too 
quick.  Considering  now  the  length  of  the 
cutting  edge,  it  may  for  heavy  chipping 
be  made  straight,  as  in  Fig.  210,  or  curved, 
as  in  Fig.  210a,  which  is  the  best  because  the 
corners  are  relieved  of  duty  and  are 
therefore  less  liable  to  break.  The  ad- 
vantage of  the  curve  is  greatest  in  fine 
chipping  because,  as  is  seen  in  Fig.  214, 
a  thin  chip  can  be  taken  without  the 
corners  cutting,  and  these  corners,  being 
exposed  to  view,  aid  the  eye  in  keeping 
the  chisel  edge  level  with  the  work  surface.  In  any  case 


Fig.  216. 


Fig.  217. 


we  must  not  grind  it  hollow  in  its 
length,  as  shown  in  Fig.  215,  and 
shown  exaggerated  in  Fig.  216,  be- 
cause in  that  case  the  corners  will 
dig  in  and  cause  the  chisel  to  be 
beyond  our  control,  and,  besides  that, 
there  will  be  a  force  that,  acting  on 
the  wedge  principle  and  in  the  direc- 
tion of  the  arrow,  will  act  to  spread  the  corners  and  break 
them  off*. 


260  COMPLETE  PRACTICAL  MACHINIST. 


VISE-  WORK— TOOLS. 


261 


The  facets  must  not  be  ground  wider  on  one  side  than 
on  the  other  of  the  chisel,  as  in  Fig.  215,  because  in  that 
case  the  flat  of  the  chisel  will  not  form  a  guide  as  to  when 
the  cutting  edge  is  fair  and  level  with  the  work  surface. 
The  length  of  the  cutting  edge  should  be  at  a  right  angle 
to  the  chisel  body,  for  if  ground  to  one  side,  as  in  Fig. 
217,  the  chisel  will  be  apt  to  jump  sideways  at  each 

blow. 

Fig.  221. 


When  a  heavy  chip  is  to  be  taken  over  a  surface  broader 
than  the  chisel,  the  cross  cut  cape  chisel,  shown  in  Fig. 
218,  is  brought  into  requisition,  being  employed  to  cut 
grooves,  as  shown  at  A  B  and  C  in  Fig.  224,  these  grooves 
being  spaced  apart  a  little  less  than  the  chisel  width,  so 
as  to  relieve  the  chisel  corners  from  duty,  and  thus  pre- 


262 


COMPLETE  PRACTICAL  MACHINIST. 


vent  them  from  breaking.  The  point  A  should  be  tapered 
back  to  B,  so  that  the  chisel  may  be  moved  laterally  to 
keep  the  cut  in  a  straight  line,  which  could  not  be  done  if 
the  end  were  made  parallel,  as  at  C  in  the  figure. 

The  round-nosed  chisel,  Fig.  219,  may  be  made  straight 


Fig.  222. 


Fig.  223. 


from  H  to  G,  but  should  be  bevelled  from  G  to  the  point, 
so  that  the  depth  of  the  cut  may  be  altered  at  will  by 
raising  or  lowering  the  chisel  head,  and  the  same  remarks 
apply  to  the  cow  mouth  chisel,  in  Fig.  220.  The  oil  groove 
chisel  shown  in  Fig.  221  is  employed  to  cut  oil  grooves  in 


VISE-WORK^-TOOLS.  26B 

the  bores  of  brasses  or  journal  boxes,-  and  should  have  a 
less  curvature  than  the  bore  of  the  brass  or  box.  It 
should  be  made  thinner  at  A  than  at  the  cutting  edge,  to 
prevent  any  wedging  action,  which  would  raise  a  burr  on 
each  side  of  the  oil  groove. 

Fig.  224. 


The  diamond  point  chisel,  shown  in  Figs.  222  and  223, 
is  for  cutting  out  square  corners,  and  is  varied  in  shape  to 
suit  the  work.  When  the  hole  in  the  work  is  not  deep,  the 
chisel  can  be  bevelled  at  M,  and  thus  bring  its  point  X 
central  to  the  body  of  the  steel,  as  shown  by  the  dotted 


264  COMPLETE  PRACTICAL  MACHINIST. 

line  Q,  rendering  the  corner  X  less  liable  to  break,  which 
is  the  great  trouble  with  this  chisel.  But  as  the  bevel  .at 
M  necessitates  the  chisel  being  leaned  over,  as  at  Y  in  Fig. 
224,  it  could  not  be  kept  to  its  cut  in  deep  holes ;  so  we 
must  omit  the  bevel  at  M,  and  make  that  edge  straight  as 
at  R  R  in  Fig.  223. 

The  side  chisel  obeys  just  the  same  rule,  so  we  must 
give  it  bevel  at  W  in  Fig.  225  for  shallow  holes  and  lean 
it  over,  and  leave  it  very  nearly  straight  for  deep  ones. 

Applications  of  chisels  are  shown  in  Fig.  224,  the  cut 
of  a  flat  one  being  shown  at  D,  the  cow  mouth  being 
shown  at  L,  the  diamond  point  at  Y,  and  the  side  chisel 
at  Z. 

Fin.  225. 


In  tempering  a  chisel,  the  end  should  first  be  dipped 
about  half  an  inch  in  the  water  and  held  still ;  it  should 
then  be  dipped  another  half  an  inch  and  quickly  with- 
drawn and  lowered  down  to  a  blue.  This  will  give  a  deep 
band  of  blue  temper,  and  the  chisel  may  be  ground  many 
times  without  losing  its  temper,  and  it  will  be  less  liable 
to  break.  In  exceptional  cases  the  temper  may  be  left  a 
little  higher,  as  say  a  reddish  purple  for  hard  steel ;  but  in 
this  case,  heavy  hammer  blows  must  not  be  given,  as  they 
will  break  the  chisel.  To  prevent  the  work  from  break- 
ing out  at  the  end  of  the  chisel  cut,  the  edges  of  the  work 
should  be  bevelled  or  chamfered  off"  as  in  Fig.  224  at  E 
and  F. 

CALIPERS. 

Outside  calipers,  that  is,  those  used  for  measuring  exter- 
nal diameters,  should  have  larger  rivets  in  them  than  they 


VISE-  WORK— TOOLS. 


265 


are  generally  given,  a  fair  proportion  being  a  rivet  of  one- 
half  inch  diameter  for  a  pair  of  calipers  intended  to  meas- 
ure up  to  diameters  of  seven  inches.  The  points  of  such 
calipers  should  be  tapered  to  a  wedge  shape,  the  tapering 
face  being  on  the  outside  edge,  so  that  the  same  part  of  the 
points  of  each  leg  will  touch  the  work,  whether  the  latter 
is  of  small  or  large  diameter ;  the  points,  where  they  meet 
together,  should  be  slightly  rounding,  so  that  they  will 
touch  the  work  at  the  middle  of  each  point. 


Fig.  226. 


Fig.  227. 


Figs.  226  and  227  represent  excellent  shapes  for  inside 
and  outside  calipers. 

The  short  angular  ends  of  the  inside  calipers  enable 
them  to  enter  a  long  distance  in  small  holes. 

The  spring  calipers  sold  at  the  stores  serve  very  well 
for  rough  measurements,  but  are  not  suitable  for  very  fine 
ones.  Furthermore,  when  operated  by  a  wing  nut,  the 
same  is  apt  to  be  moved  in  laying  the  calipers  down.  The 
forms,  however,  in  which  the  legs  are  moved  by  a  right 
and  left  hand  screw  are  excellent  when  means  are  pro- 
vided for  locking  the  screw. 


266  COMPLETE  PRACTICAL  MACHINIST. 

-  Another  feature  to  the  advantage  of  this  form  is,  that 
when  the  legs  are  extended,  the  points  are  still  at 'the 
extreme  end  of  the  calipers,  so  that  the  points  will  meas- 
ure to  the  extreme  end  of  the  hole,  even  though  the  latter 
is  closed  by  metal,  that  is,  terminates  in  the  metal.  This 
is  not  the  case  when  the  caliper  ends  are  bent  round  to  the 
usual  extent,  for  the  curve  of  the  bend  will  touch  the  end 
of  the  hole  and  prevent  the  caliper  points  from  reaching 
it.  In  measuring  with  calipers,  let  the  points  be  set  to 
touch  the  work  very  lightly  indeed,  or  they  will  spring 
from  the  pressure  due  to  forcing  them  over  the  work. 

Compass  calipers  should  have  the  end  of  one  leg  bent 
round  at  the  end,  about  the  same  as  is  customary  for  inside 
calipers,  the  other  leg  being  pointed  like  a  compass  leg. 
They  are  valuable  tools,  and  may  be  employed  to  mark  off 
the  centres  of  holes,  or  to  try  if  a  centre  already  existing  is 
in  the  exact  centre  of  the  hole.  Or  they  will  mark  off  a 
face,  so  that  it  will  fit  another  face,  whether  it  be  regular 
or  irregular,  the  curved  point  being  kept  against  the  irreg- 
ular face,  and  the  point  describing  (by  moving  the  com- 
pass along)  a  similar  line  on  the  face  to  be  fitted.  They 
will  answer  for  many  of  the  uses  to  which  a  scribing  block 
is  put ;  and  being  lighter  and  more  easily  handled,  and, 
furthermore,  capable  of  doing  duty  without  the  use  of  a  sur- 
face or  scribing  plate,  they  are  in  such  cases  far  preferable. 
The  legs  may  be  crossed  so  that  the  curved  point  inclines 
to  the  straight  point,  in  which  position  they  will  mark  the 
centres  of  shafts  or  rods,  either  round,  square,  or  any  other 
shape,  or  try  such  centres,  when  they  already  exist,  more 
accurately  than  can  be  done  by  any  other  tool.  They  will, 
in  this  case,  mark  off  a  line  at  the  distance  to  which  they 
are  set  round  any  surface ;  they  are  employed  to  mark  off 
keyways,  or  the  taper  of  a  gib  when  the  key  and  one  edge 
of  the  gib  is  placed,  and  for  a  variety  of  other  uses  too 
numerous  to  recapitulate,  being  among  the  most  useful 
tools  the  fitter  can  possibly  possess.  The  points  of  calipers 


VISE-  WORK— TOOLS.  267 

should  be  tempered  to  a  blue,  and  of  compass  calipers  to  a 
straw  color. 

THE   SQUARE. 

The  square  is  too  common  a  tool  to  require  any  descrip- 
tion of  its  form.  The  best  method  to  make  one  is  to  make 
the  back  of  steel,  and  in  two  halves,  one-half  being  the 
thickness  of  the  blade  thicker  than  the  other.  The  slot  for 
the  blade  must  then  be  filed  in  the  thickest  half,  to  the 
depth  exactly  equal  to  the  thickness  of  the  blade.  The 
two  halves  composing  the  back  must  then  be  riveted  to- 
gether, and  the  edges  surfaced  each  true  of  itself  (using 
a  surface  plate  to  try  them),  and  also  true  with  each 
other.  The  blade,  which  should  be  made  of  saw  blade, 
may  then  be  put  into  its  place,  ready  to  have  the  holes  for 
the  rivets  drilled.  It  should  be  placed  so  that  the  outer 
end  is  a  little  depressed  (on  the  inside  angle)  from  the 
right  angle;  this  is  done  so  that  whatever  there  may  be  to 
take  off  the  blade  (after  it  is  riveted  to  the  back),  to  make 
its  edges  form  right  angles  to  the  back,  will  require  to  be 
taken  off  the  outer  end  of  the  inside  angle  and  the  end  of 
the  blade  forming  the  corner  of  the  outside  angle,  so  that 
no  work  will  require  performing  on  the  blade  in  the  cor- 
ner formed  by  the  blade  entering  the  back  on  the  inside 
angle,  where  it  would  be  difficult  to  file  or  scrape  without 
injuring  the  edge  surface  of  the  back.  The  best  way  to 
true  a  square  is  to  turn  up  a  piece  of  round  iron  equal  in 
length  to  the  square  blade,  being  careful  to  make  it  quite 
parallel,  and  then  true  up  the  end  of  the  iron,  making  it 
hollow  towards  the  centre,  or  cutting  it  a\\ay  from  the 
centre  to  within  an  eighth  of  an  inch  of  its  diameter,  so 
that  it  will  stand  steadily  on  its  end.  If  the  piece  of  iron 
be  then  stood  on  its  end  on  a  surface  plate,  its  outline  on 
each  side,  which  represents  its  diameter,  will  form  a  true 
right  angle  to  the  surface  of  the  plate,  and  hence  a  gauge 
with  which  to  true  the  square. 


268 


COMPLETE  PRACTICAL  . MACHINIST. 


THE   SCRIBING   BLOCK. 

This  tool  is  made  in  a  variety  of  forms,  but  the  simplest 
and  best  form  is  that  shown  in  Fig.  228,  in  which  D 
is  the  block  complete,  the  scriber  being  a  simple  piece 
or  round  steel  wire.  The  dotted  line  on  the  foot  is  the 
distance  to  which  the  foot  is  hollowed  out  to  make  it  stand 
firm.  Fig.  E  is  the  bolt  and  nut;  the  bolt  has  a  flat 
side  filed  on  each  side  of  it  to  fit  it  to  the  slot  in  the 
scribing  block  stem,  so  that  the  bolt  cannot  turn  when 

Fig.  228. 


it  is  being  tightened.  Fig.  F  is  a  face  and  edge  view  of 
the  piece  or  clamp  for  the  scriber  which  passes  through 
the  hole  in  the  slot. 

The  advantages  possessed  by  this  form  over  other  forms 
of  scribing  block  are  that  it  is  easy  to  make,  and  that  the 
scriber,  being  a  piece  of  wire,  is  easily  renewed.  It  holds 
the  scriber  very  firmly  indeed,  and  the  scriber  may  be 
moved  buck  and  forth  without  the  nut  becoming  slack. 


VISE-  WORK— TOOLS.  269 

FILES   AND   FILING. 

Large  files  should  be  fitted  to  their  handles  by  making 
the  tine  of  the  file  a  low  red  heat,  and  forcing  it  into  the 
handle  so  that  it  will  burn  its  way  into  the  handle,  and 
thus  prevent  the  handle  from  splitting,  as  it  would  do  if 
the  file  tine  were  driven  in ;  the  file  and  handle  should  be 
turned  in  the  hands  occasionally  to  guide  the  eye  in 
detecting  whether  the  file  is  entering  in  a  line  with  the 
length  of  the  handle.  Care  should  be  taken  to  wrap  a 
piece  of  waste  around  the  end  of  the  file,  and  to  keep  it 
wetted  with  water  so  as  to  avoid  softening  the  teeth  of  the 
file  while  heating  the  tine.  For  small  files  it  is  sufficient 
to  bore  a  small  hole  in  the  handle  and  force  the  tine  in  by 
hand.  A  file  should  be  held  so  that  the  butt  end  of  the 
file  handle  presses  against  the  centre  of  the  palm  of  the 
hand,  the  forefinger  being  beneath  the  body  of  the  file 
handle. 

In  selecting  a  file,  choose  one  that  is  thickest  in  the 
centre  of  its  length,  and  of  an  evenly  curved  sweep  from 
end  to  end,  so  as  not  to  make  the  surface  of  the  work 
round  by  filing  away  the  edges.  Files  that  have  warped  in 
the  hardening  may  be  used  on  very  narrow  surfaces,  or  on 
round  or  oval  work  ;  or,  if  they  are  smooth  files,  they  may 
be  used  on  lathe  work.  Key  ways  or  slots,  especially, 
require  an  evenly  rounded  file ;  and  if  the  key  way  is  long 
and  the  file  parallel  or  uneven  upon  its  surface,  the  end 
of  the  file  only  should  be  used  to  ease  away  the  centre 
of  the  key  way  or  the  high  spots.  It  is  also  highly  advan- 
tageous to  rub  chalk  on  the  teeth  of  the  file,  so  that,  after 
a  little  using,  the  eye  can  detect  the  part  of  the  file  which 
is  highest,  and  govern  its  use  accordingly. 

Half-round  files  should  be  rounded  lengthwise  of  the 
half-round  side  of  the  file,  because  it  is  difficult  to  file  out 
a  sweep  evenly,  even  with  a  well-shaped  file,  and  it  is 
impossible  to  do  so  with  a  file  whose  half-round  surface  is 
hollow  in  the  direction  of  its  length. 
23- 


270 


COMPLETE  PRACTICAL  MACHINIST. 


Files  should  be  held  as  in  Fig.  229,  the  end  of  the 
handle  abutting  against  the  palm  of  the  hand,  and  on 
broad  surfaces  should  be  used  with  a  lateral  sweep  at 


Fig.  229. 


fig.  230. 


each  stroke,  so  that  the  file  marks  will  cross  and  recross, 
as  in  Fig.  230.  When  a  raised  handle,  such  as  in  Fig. 
231,  is  used,  the  most  rounded  or  bellied  side  of  the  file 


VISE-  WORK— TOOLS. 


271 


should  be  applied  to  the  work,  so  as  to  confine  the  duty 
to  as  few  teeth  as  possible,  and  thus  enable  the  file  to  cut 
more  freely. 


Fig.  231. 


In  using  a  half-round  file,  to  file  out  a  curve,  the  file 
should  be  given  a  lateral  sweep,  first  from  right  to  left, 
and  then  from  left  to  right,  changing  the  direction  after 


Fig.  232. 


every  few  strokes,  which  will  prevent  the  formation  of  such 
waves  as  are  shown  in  Fig.  232.  And  in  draw  filing,  the 
unit  should  so  bend  at  each  file  stroke  that  different  parts 


*72  COMPLETE  PRACTICAL  MACHINIST. 

of  the  file  meet  the  work  at  every  part  of  its  motion,  as  is 
shown  in  Fig.  233.  At  the  same  time,  however,  it  is 
necessary,  at  each  stroke,  to  move  the  file  endways  a  trifle 
front  in  one  direction  and  then  in  the  other,  so  that  the 


2:53. 


file  marks  cross  each  other,  and  thereby  produce  an  even 
curvature  on  the  work. 

FILING   OUT   TEMPLATES. 

Let  it  be  required  to  make  or  test  a  piece  of  work  such 
as  in  Fig.  234,  the  teeth  to  be  equally  spaced,  of  the  same 
angle,  and  of  equal  height.  A  template  must  be  made  of 
the  form  shown  in  Fig.  235.  To  begin  with,  take  a  piece 
of  sheet  metal  equal  in  width  to  at  least  two  teeth,  and 
assuming  that  the  template  is  to  have  two  teeth,  file  its 
sides,  P  Q,  in  Fig.  236,  parallel,  and  make  the  width 
equal  to  twice  the  pitch  of  the  teeth.  We  next  divide  its 
width  into  four  equal  parts  by  lines,  and  mark  the  height, 
as  shown  in  Fig.  236.  If  we  desire  to  make  the  template 
such  as  at  1  in  Fig.  235,  we  cut  out  the  shaded  portion 


VISE-  WORK— FILING    TEMPLA  TES. 


273 


at  A,  Fig.  236 ;  or  for  the  template  at  2,  Fig.  235,  the 
shaded  portion  at  B.  It  will  be  observed,  however,  that 
in  template  A,  Fig.  236,  there  are  two  corners,  C  and  D, 
to  be  filed  out,  while  at  B  there  is  but  one  (E),  the  latter 


Fig.  234. 


Fig.  235. 


Fig.  236. 


being  the  easier  to  make,  since  the  corners  are  the  most 
difficult  to  file  and  keep  true.  The  best  method  of  pro- 
ducing such  a  corner  is  to  grind  the  teeth  off  with  a  half- 
round  file  on  the  rounded 
side,  producing  a  sharper 
corner  than  the  teeth  possess, 
while  giving  at  the  same  time 
a  safe  edge  that  will  not  cut 
one  angle  while  the  other  is 
being  filed.  But  when  we 
come  to  apply  these  templates 

to  the  work,  we  shall  find  that  A  is  the  better  of  the  two, 
because  we  can  apply  the  square  S  (Fig.  237)  to  the  out- 
side of  the  template,  and  also  to  the  edge  F.of  the  work, 
which  cannot  be  done  to  the  edges  G  of  the  work  and  H 
of  the  template,  because  the  template  edge  overhangs. 
We  can,  however,  apply  a  square,  S',  to  the  other  edge 
of  B,  but  this  is  not  so  convenient  unless  the  tops  of  the 
teeth  are  level. 

Assuming,  therefore,  that  the  template  A  is  the  one  to 
be  made,  we  proceed  to  test  its  accuracy,  bearing  in  mind 
that  for  this  purpose  the  same  method  is  to  be  employed, 
whatever  shape  the  template  may  be.  Consequently,  we 
make  from  the  male  template  A,  Fig.  238,  a  female  tern- 


274 


COMPLETE  PRACTICAL  MACHINIST. 


plate,  K,  Fig.  239,  beginning  at  one  end  of  K  and  tiling 
it  to  fit  A  until  the  edges  of  A  and  K  are  in  line  when 
tested  by  a  straight-edge,  S.  We  then  move  the  templat3 


Fig.  237. 


A  one  tooth  to  the  right,  and  file  another  tooth  in  K,  and 
proceed  in  this  way  until  a  number  of  teeth  have  been 
made,  applying  a  square  as  at  S,  Fig.  238,  to  see  that  the 

Fig.  238. 


template  A  is  kept  upright  upon  K.  When  K  has  been 
thus  provided  with  several  teeth  that  would  fit  A  in  any 
position  in  which  the  latter  may  be  placed,  we  must  turn 


VISE-WORK—FILING    TEMPLATES. 


27--, 


template  A  around  upon  K  to  test  the  equality  of  the 
angles.  Thus,  suppose  at  the  first  filing  the  edges  abed 
upon  A  accurately  fit  the  template  K,  and  the  straight- 
edge shows  the  edges  fair.  Then  if  we  simply  turn  the 
template  A  around,  its  angles,  which  were  before  on  the 
right,  will  now  be  on  the  left,  as  is  shown  at  the  right  of 
Fig.  239.  Thus  in  one  position  a  fits  to  c,  in  the  other  it 
fits  to  h,  or  b  fits  to/,  and  when  turned  around  it  fits  to  <7, 
and  so  on.  Supposing  that  when  thus  turned  around  the 

Fig.  239. 


angles  do  not  coincide,  then  half  the  error  will  be  in  tho 
teeth  of  A,  and  one-half  in  those  of  K,  and  the  best  plan 
will  be  to  correct  them  on  A  to  the  necessary  amount  as 
near  as  judgment  will  dictate,  and  then  to  apply  K  as 
before,  continuing  this  process  until  A  will  fit  anywhere  in 
K,  and  may  be  turned  around  without  showing  any  error. 
But  at  each  correction  the  straight-edge  must  be  applied, 
and  finally  should  be  tried  to  prove  if  the  teeth  tops  are 
level.  We  have  two  interchangeable  templates,  of 


276  COMPLETE  PRACTICAL    MACHINIST. 

A  may  be  used  on  the  work  and  K  kept  to  correct  A 
when  the  latter  becomes  worn.  It  may  be  as  well  to  add, 
however,  that  in  first  applying  A  to  K  it  is  best  to  press 
the  straight-edge  S  against  the  edge  of  K,  and  hold  it 

Fig.  240. 


there,  and  then  to  place  it  against  S,  and  slide  it  down 
into  K. 

Fig.  240  represents  an   example  in  which,  the  form 
being  a  curve,  it  would  be  best  to  have  the  template  touch 

Fig.  241. 


more  than  two  teeth,  as  shown  in  the  cut.  By  letting  the 
side  A  of  the  template  T  terminate  at  the  centre  line  of 
the  two  curves,  and  the  end  B  terminate  at  the  top  of  a 
curve,  turning  the  template  around  would  cause  end  A  to 
envelope  side  C  of  the  middle  curve,  thus  increasing  the 


VISE-  WORK— FILING    TEMPLA I ES. 


277 


scope  of  the  template.  Suppose,  however,  that  the  base 
curve  D  required  to  be  true  with  the  teeth  then  a  second 
template  T  must  be  used,  its  ends  at  E  and  F  measuring 
an  equal  length  or  height,  so  that  when  they  are  placed 
even  with  the  ends  of  the  work,  the  distances  G  H  being 
equal,  the  corrugations  will  be  true  to  the  curve  D  D. 

Fig.  242. 


Now  let  it  be  supposed  that,  instead  of  making  a  template 
to  test  a  piece  of  work  such  as  W  iu  Fig.  240,  it  is  re- 
quired to  make  a  template  for  use  in  making  another 
piece  of  work  that  is  to  fit  to  piece  W ;  then  template  T 
in  Fig.  240  will  not  answer,  because  it  is  a  female 
template,  whereas  a  male  one  is  required,  so  that  the  edge 


Fig.  243. 
' 


of  the  template  may  coincide  with  that  of  the  work.  But 
we  may  convert  T  (Fig.  240)  into  a  male  template  by 
simply  cutting  off  the  edge  A  as  far  as  the  line  J,  leaving 
it  as  at  T  in  Fig.  242,  and  causing  its  right-hand  edge  to 
coincide  with  the  edge  of  the  work  so  that  the  latter,  after 
being  fitted  to  the  template,  may  be  turned  upside  down 
and  fit  upon  the  piece  of  work  W,  Fig.  241,  which  eor- 
24 


278 


COMPLETE  PRACTICAL  MACHINIST. 


responds  to  the  piece  W,  Fig.  240.  Fig.  243  represents 
an  example  in  which  the  forms  of  both  sides  of  a  piece 
require  to  be  exactly  alike,  and  the  easiest  method  of  ac- 
complishing this  is  as  follows:  The  edge  A  should  first  be 
made  true,  and  edge  B  made  parallel  to  A.  A  centre 
line,  C,  may  then  be  drawn,  and  from  it  the  lines  E  E 


Fig.  244. 


may  be  marked.  The  lines  D  are  then 
drawn  parallel  to  A  A,  lines  E  being 
made  square  to  D  and  to  A.  The  sides 
E  may  be  calipered  to  width  and 
parallelism,  and  all  that  will  then  re- 
main is  to  file  the  angles  F  F  and  thn 
ends  G  G  to  their  required  lengths.  For  F  F  all  that  13 
necessary  is  a  template  formed  as  in  Fig.  244.  The  object 
of  dressing  the  ends  G  G  last  is  that  if  they  were  finished 
before,  their  faces  E  would  have  to  be  made  at  exactly 
correct  distances  from  them,  which  would  render  the  job 
considerably  more  difficult. 


Fig.  245  represents  a  sketch  for  a  piece  of  work  whoso 
two  sides  are  to  be  shaped  exactly  alike,  requiring  a 
template  of  the  form  shown.  From  this  a  second  ttm- 
plate,  M,  Fig.  246,  is  made,  and  to  this  latter  the  work 
may  be  filed.  To  make  the  template  in  Fig.  245  the 
edge  x  x  must  be  made  straight,  and  the  edge  D  parallel 
to  it  at  the  proper  height.  A  centre  line,  S,  is  then 


VISE-  WORK— FILING    TEMPI  A  TES. 


279 


marked,  and  the  edges  at  E  may  be  filed  equidistant  from 
S  and  square  to  D ;  hence  they  will  be  parallel  to  each 
other.  The  side  sections  F  should  then  be  filed  equidis- 
tant from  S  and  parallel  to  each  other.  They  should  be 
the  proper  width  apart  and  square  to  D,  being  tested  in 

Fig.  246. 


each  of  these  respects.     The  line  joining  E  and  F  should 
be  left  full,  as  denoted  by  the  dotted  line  at  A  on  the 
right.     The  edges  at  C  C  should  then  be  filed,  calipering 
them  from  the  edge  x  x.     Edges  G  G  are  obviously  equi- 
distant from  S  and  parallel  to  S,  or,  what  is  the  same 
thing,  at  a  right  angle  to  x  x,  from          j-..    ~A* 
which  they  may  therefore  be  tested  with 
a  square,  and,  finally,  the  edges  B  are 
made  parallel  to  x  x,  and  the  ends  II 
made  square  to  x  and  equidistant  from 
S.     We  have  now  to  file  the  angular 
groove  at  A,  and  to  get  this  true  after 
marking  its  depth  from  the  lines  at  A, 
we  file  it  first  to  the  lines  as  near  as  illilllllllllllll'llllllllllllllllllii 
may  be  by  the  eye  and  very  nearly  to 
the  full  depth.      We  then  make  a  small  supplemental 
male  template  equal  in  width  to  the  distance  E  F,  or,  in 
other  words,  to  the  width  of  the  step  at  A,  and  having  its 
edges  quite  parallel.     Its  end  is  then  filed  to  fit  the  groove 
at  A,  when  its  edge  meets  and  coincides  with  edge  E,  as 


280  COMPLETE  PRACTICAL  MACHINIST. 

in  Fig.  246,  T  representing  the  supplemental  template. 
It  is  clear  that  when  the  V-groove  A  is  so  filed  that  T  will 
fit  it  with  either  of  its  edges  against  E,  the  angles  of  the 
groove  will  be  alike,  and  we  may  then  make  a  male 
gauge,  as  in  Fig.  247,  that  may  be  used  to  mark  or  line 
out  the  work  and  to  use  a  template  to  file  it  to,  its  edge  H 
being  kept  parallel  to  face  D  (Fig.  245)  of  the  work. 

SCRAPERS   AND   SCRAPING. 

Surfaces  requiring  to  be  made  very  true  may  be  finished 
by  the  hand-scraping  process,  but  as  filing  is  much  quicker 
than  scraping,  the  work  should  be  filed  as  true  as  possible 
before  the  scraper  is  applied  to  it.  Fig.  248  represents  an 

Fig.  248. 


ordinary  form  of  hand  scraper,  and  Fig.  249  a  form  that 
will  cut  somewhat  smoother.  For  use  on  wrought-iron, 
the  cutting  edge  should  be  kept  moistened,  or  it  will  tear 
the  metal  instead  of  cutting  it  cleanly.  All  surfaces 
intended  to  be  scraped  should  first  be  filed  as  true  as 

Fig.  249. 


possible  with  a  smooth  file,  care  being  exercised  to  use 
a  file  that  is  evenly  curved  in  its  length  and  slightly 
rounding  in  its  breadth.  After  the  surface  has  been 
scraped  once  or  twice,  a  well-worn,  dead  smooth  file  may 
be  passed  over  it,  which  will  rub  down  the  high  spots 


VISE  WORK—  FTL  ES.  281 

of  the  scraper  marks  and  greatly  assist  the  operation  of 
scraping.  Scraping  should  he  executed  in  small  squares,  the 
marks  of  one  square  being  at  a  right  angle  to  the  marks  of 
the  next ;  then,  after  the  surface  plate  has  been  applied,  re- 
peat the  operation  of  scraping  in  squares,  but  let  the  marks 
cross  those  of  the  previous  scraping.  The  face  of  the  sur- 
face must  be  wiped  off  very  clean  before  the  surface  plate 
is  applied,  or  the  surfaces  of  both  the  plate  and  the  work 
will  become  scratched.  The  face  of  the  plate  may  be 
moistened  by  the  application  of  a  barely  perceptible  coat 
of  Venetian  red,  mixed  with  lubricating  oil,  rubbed  on  by 
the  palm  of  the  hand,  to  operate  as  marking  to  denote  the 
high  spots.  In  applying  the  surface  plate,  move  it  both 
ways  on  the  work,  and  reverse  it  endwise  occasionally.  If 
the  work  is  light,  it  may  be  taken  from  the  vise  and  laid 
upon  the  plate  ;  but  much  pressure  need  not  be  placed 
upon  the  work,  or  it  will  spring  to  suit  the  surface  of  the 
plate,  and  thus  appear  to  be  true  when  it  is  not  so.  Small 
surfaces  should  be  rubbed  on  the  outer  parts  of  the  surface 
of  the  plate,  by  which  means  the  wear  on  the  surface  plate 
will  be  kept  more  equal. 

VISE  CLAMPS. 

To  prevent  the  jaws  of  a  vise  from  damaging  finished 
work,  we  require  a  pair,  each,  of  lead  and  copper  clamps. 
Two  pieces  of  sheet  copper  T\  inch  thick,  the  width  of  the 
vise  jaws  one  way  and  about  six  inches  the  other,  will 
answer  to  make  the  copper  clamps.  The  first  operation  is 
to  soften  them  by  heating  them  to  a  low  red  heat  and  dip- 
ping them  in  cold  water  or  brine.  We  then  take  one  of 
the  pieces  of  copper  and  grip  it  in  the  vise,  so  that  it  just 
covers  but  does  not  project  below  the  gripping  faces  of  the 
vise  jaws,  and  bend  the  upper  part  over  to  fit  the  outer  face 
of  one  vise  jaw,  making  it  fit  the  latter  neatly  all  over  and 
hammering  it  so  as  to  bring  the  edge  nearly  sharp.  We 
then  take  it  from  the  vise  and  soften  it  again,  and  replacing 
24* 


282  COMPLETE  PRACTICAL  MACHINIST. 

it  in  the  vise,  hammer  it  on  the  upper  surface  till  the  edge 
is  sharply  defined.  We  then  operate  upon  the  other  piece  of 
copper  in  like  manner,  thus  producing  a  pair  of  clamps  that, 
having  sharply  defined  and  not  rounded,  gripping  edges, 
will  hold  a  thin  piece  of  work  above  the  upper  face  of  the 
clamps  without  springing  the  work  out  of  the  vice.  The 
object  of  having  the  upper  surface  of  the  copper  so  long  is 
so  that  it  will  bend  far  over  the  upper  surface  of  the  vise 
jaw,  and  will  not  be  liable  to  fall  off  when  the  vise  jaws 
are  opened. 

Since  copper  clamps  become  hardened  through  use,  it  is 
necessary,  when  they  become  glazed,  to  soften  them. 

Lead  clamps  are  usually  made  as  wide  as  the  vise  jaws, 
the  part  covering  the  gripping  faces  of  the  vise  jaws  being 
of  the  same  depth  as  those  faces  and  about  f  inch  thick, 
the  upper  face  of  each  clamp  which  laps  over  the  upper 
jaws  of  the  vise  well  covering  the  latter  and  being  about 
I  inch  thick.  Both  lead  and  copper  clamps  are  apt  to  get 
filings  and  grit  embedded  in  their  surfaces;  hence  on  deli- 
cate work  it  is  well  to  either  place  a  piece  of  rag  or  cloth 
over  them,  or  else  to  use  a  pair  of  leather  clamps,  say  I 
inch  thick,  the  leather  being  cut  through  about  halfway  to 
cause  it  to  bend  over  the  vise  jaws  and  not  fall  off  when 
the  vise  jaws  are  opened. 

Work  which  presents  a  small  gripping  surface  to  the 
vise  jaws,  such  for  instance  as  round  bolts  or  spindles,  can 
be  held  more  firmly  by  lead  than  by  copper  clamps,  be- 
cause the  work  will  sink  into  the  lead  when  the  vise  is 
tightened. 

VISE    WORK — PENING. 

The  operation  termed  pening  is  stretching  the  skin  on 
one  side  of  work  to  alter  its  shape,  the  principle  of  which 
is  that,  by  striking  metal  with  a  hammer,  the  face  of  the 
metal  struck  stretches,  and  tends  to  force  the  work  into  a 
circular  form,  of  which  the  part  receiving  the  effect  of  the 
hammer  is  the  outside  circle  or  diameter. 


VISE-  WOEK—PENING. 


283 


Fig. 250  represents  a  piece  of  flat  iron,  which  would,  if  it 
Fig.  250. 


a 


Fig.  251. 


•were  well  hammered  on  the  face,  a,  a,  a,  with  the  pene  of  a 
hammer,  alter  its  form  to  that  denoted  by  the  dotted  lines. 
Fig.  251  represents  a  brass  which,  it  struck  with  a  ham- 
mer (along  its  bore  at  a)  or 
other  piece  of  metal  for  driving 
it  in  while  fitting,  would  grad- 
ually assume  the  form  denoted 
by  the  dotted  lines.  Fig.  252 
represents  a  rod  connected  at 
the  end  a  with  a  double  eye 

and  pin,  and  requiring  to  descend  true  so  as  to  fit  into  the 
double  eye  b,  at  the  other  end ;  if,  therefore,  it  is  pened 
perpendicularly  on  the  face  c  of  the  rod,  the  stretched 

Fig.  252. 


skin  will  throw  the  end  around  so  that  it  will  come  fair 
with  the  eye  b.  Connecting  rod  straps  which  are  a  little 
too  wide  for  the  rod  ends  may  be  in  like  manner  closed  so 
as  to  fit  by  pening  the  outside  of  the  crown  end,  or,  if  too 
narrow,  may  be  opened  by  peniug  the  inside  of  the  crown 
end  ;  but  in  either  case  the  ends  of  the  strap  alter  most 
in  consequence  of  their  lengths,  and  the  strap  will  require 
refitting  between  its  jaws. 

Piston  rings  may  be  made  of  a  larger  diameter  by  pen- 
ing  the  ring  all  round  on  the  inside,  and  there  are  many 
other  uses  to  whicli  p°nin<r  may  be  used  to  advantage, 
such  as  setting  frames,  refitting  old  work,  taking  the  twist 


284  COMPLETE  PRACTICAL  MACHINIST. 

out  of  work,  etc. ;  but  it  must  be  borne  in  mind  that  if, 
after  a  piece  of  metal  has  been  pened,  a  cut  is  taken  off  it, 
it  will  return  to  its  original  shape,  as  the  effects  of  the 
pen  ing  do  not  extend  more  than  6V  of  an  inch  in  depth. 
When,  therefore,  a  brass  or  other  work  requiring  to  be 
bored  is  driven  in  and  out  by  a  piece  of  metal  or  a  ham- 
mer, it  stretches  the  skin  ;  and  when  the  brass  is  bored, 
the  stretched  skin  being  cut  away,  it  assumes  its  original 
shape  and  hence  becomes  slack  or  loose  in  the  strap  or 
block.  A  light  hammer  having  a  round  pene  should  be 
used;  and  light  blows  should  be  employed  for  peiiing,  as 
they  are  the  most  effective. 

FITTING   BRASSES   TO   THEIR    BOXES. 

The  pattern  for  a  brass  which  is  hexagonal  upon  the 
bottom  or  bedding  part  should  not  be  made  of  exactly  the 
same  shape  as  the  hexagonal  part  of  the  box  upon  which  it 
beds,  because  the  brass,  in  casting,  shrinks  in  the  direction 
of  the  diameter  of  the  bore  to  such  an  extent  as  seriously  to 
alter  the  angles  of  the  bottom  of  the  brass  as  compared 
with  the  angles  on  the  bottom  of  the  pattern.  To  com- 
pensate for  this  change  of  form,  the  angles  on  the  sides  of 
the  pattern  should  be  made  more  obtuse  than  those  on 
the  sides  of  the  box,  as  described  in  Fig.  253,  the  dotted 
lines  being  the  angle  of  the  box.  The  shrinkage  referred 
to  is  not  merely  that  due  to  the  con- 
Fig.  253.  traction  of  the  metal  in  cooling,  but 

is  an  alteration  of  form  which  takes 
place  in  all  castings  of  more  or  less 
segmental  circular  form,  especially  in 
the  case  of  light  castings.  In  castings 
of  4  inches  or  less  diameter,  the  rap- 
ping (given  by  the  moulder  to  the  pattern  to  loosen  it  in 
the  sand,  so  as  to  be  able  to  extract  the  pattern  without  dan.- 
nging  the  mould)  is  about  equal  to  this  alteration  of  form ; 
but  in  larger  castings  an  allowance  must  be  made  for  it. 


VISE-  WORK—  FITTING    BRASSES.  285 

In  fitting  a  brass  to  its  box,  first  fit  the  sides  of  the  brass 
to  the  box,  keeping  them  at  an  equal  angle  to  the  joint  or 
top  face  of  the  brass,  so  as  to  let  the  brass  down  evenly 
and  not  with  one  side  or  one  bevel  lower  than  the  other. 
To  find  if  the  brass  is  level,  use  inside  calipers  as  a  gauge, 
applied  from  the  top  face  of  the  brass  to  the  top  face  of 
the  box.  When  the  brass  is  let  down  so  that  it  approaches 
the  bottom  of  the  box,  rub  upon  the  bed  of  the  box  a 
coating  of  marking ;  and  then  upon  the  end  of  each  bevel, 
and  upon  the  bottom  and  near  each  corner  (of  the  bevels 
and  bottom),  place  some  small  pellets  of  red  lead,  mixed 
stiffly ;  then  when  the  brass  is  driven  home  upon  its  bed 
and  again  taken  out,  the  pellets  of  red  lead  will  adhere  to 
the  box  because  of  the  marking,  and  (by  their  respective 
thicknesses)  denote  how  nearly  the  angles  or  bevels  of  the 
brass  fit  to  the  box ;  because  where  the  brass  touches  the 
bed  of  the  box,  the  pellets  will  be  mashed;  but  if  the 
pellets  are  intact,  it  demonstrates  that  there  is  space 
between  the  box  and  the  brass.  It  is  obvious  that  tho 
brass  requires  chipping  in  those  places  where  the  pellets 
are  crushed,  and  in  proportion  to  the  thickness  of  the 
pellets  that  are  the  least  crushed.  The  pellets  should  be 
removed  and  replaced  each  time  before  driving  the  brass 
home,  and  removed  when  they  appear  of  even  thicknesses, 
the  fitting  being  completed  with  marking  only.  All  brasses 
must  be  fitted  to  their  boxes  more  tightly  than  they  are 
intended  to  be  when  finished,  because  they  go  in  from  the 
process  of  boring  and  are  consequently  an  easier  fit  after 
than  before  being  bored. 

FITTING   LINK    MOTIONS. 

The  planing  and  boring  of  the  link  of  the  die,  and  of  the 
eccentric  rod  double  eyes  being  completed,  the  faces  of  the 
links  may  be  filed  up  to  a  surface  plate.  The  slot  of  the 
link  should  then  be  filed  out  to  a  gauge  of  sheet-iron  of  the 
proper  sweep,  the  sides  of  the  slot  being  kept  square  at  all 


i286  COMPLETE  PRACTICAL  MACHINIST. 

parts  with  the  face  of  the  link :  each  end  of  the  slot  at  the 
termination  of  the  stroke  of  the  die  should  be  eased  off  a 
little,  so  that,  when  the  link  and  the  die  are  hardened,  the 
latter  will  not  bind  hard  in  the  ends  of  the  former,  as 
would  otherwise  inevitably  be  the  case.  The  die  may  then 
be  fitted,  to  a  rather  tight  fit,  to  the  slot  of  the  link, 
putting  a  very  light  coat  of  marking  upon  either  or  both  of 
them,  which  will  serve  as  a  lubricant  to  prevent  them  from 
cutting,  and  will  show  the  high  spots  upon  both  the  link 
and  the  die,  which  spots  must  be  eased  off  until  the  die  fits 
to  a  working  fit,  providing  the  link  and  die  are  not 
intended  to  be  hardened.  If,  however,  they  are  to  be 
hardened,  the  die  must  be  made  of  a  somewhat  easier  fit  to 
allow  for  the  expansion  of  the  metal  which  takes  place  in 
hardening.  To  fit  the  double  eyes  (that  is,  the  eccentric 
rod  ends)  upon  the  link  (or  quadrant),  a  bolt  and  washer 
should  be  provided,  the .  pin  being  a  fit  to  the  hole  in  the 
eye  and  to  the  hole  in  the  washer,  the  head  of  the  pin  and 
the  washer  being  the  finished  diameter  of  the  outside  of  the 
eye.  The  end  of  the  pin  is  passed  through  one  side  of  the 
eye,  then  through  the  washer,  and  then  through  the  other 
side  of  the  eye. 

The  underneath  faces  of  the  pin  and  washer  will,  if 
revolved  by  hand,  mark  the  two  faces  (against  which  they 
bear)  true  with  the  hole  of  the  double  eye  ;  and  when 
those  faces  are  finished,  the  pin  may  be  turned  end  for  end, 
and  the  other  two  faces  trued  in  the  same  manner.  The 
object  of  making  the  head  of  the  pin  and  the  washer  of  the 
same  diameter  as  the  double  eye  is  that  they  may  be  used 
as  gauges  to  which  to  file  up  the  outside  of  the  double  eye, 
for  which  purpose  they  should  be  hardened  so  that  the  file 
will  not  cut  them.  The  double  eyes  being  filed  to  fit  the 
link,  the  washer  (having  been  used,  as  above  described,  as 
a  gauge  to  keep  the  faces  true  to  the  hole)  must  then  be 
clamped  to  the  link,  care  being  taken  to  make  the  holo  of 
the  link  as  true  as  possible  with  the  hole  of  the  double  eye, 


VISE-  WORK—  FITTING  LINK  MOTIONS.         287- 

and  to  slacken  the  bolt  of  the  clamp  if  the  double  eye 
requires  moving  to  come  fair  with  the  hole  in  the  link.  If 
the  clamp  were  not  slacked,  striking  the  double  eye  to 
move  it  would  probably  spring  one  jaw  out  of  true  with 
the  other.  A  hand  reamer  may  be  passed  through  the 
double  eye,  taking  out  a  light  cut,  and  thus  making  the 
holes  through  the  link  and  double  eye  parallel  and  quite 
true  with  each  other. 

If,  after  the  link  has  been  hardened,  the  die  is  too  tight 
a  fit,  place  oil  and  fine  emery  in  the  slot,  put  the  die  in 
its  place  and  (with  a  piece  of  wood  through  the  hole  of 
the  die)  force  it  back  and  forth  from  end  to  end  of  the  slot, 
or  in  such  parts  only  as  it  may  be  too  tight ;  this  will 
grind  out  the  tight  places.  If  there  is  no  fine  emery  at 
hand,  crush  some  coarse  emery,  using  a  hammer  and  a 
block  of  iron.  If  the  link  is  tight  at  the  extreme  ends,  as 
is  sometimes  the  case,  a  piece  of  flat  copper  shaped  and 
used  as  a  file  may  be  used  with  grain  emery  and  oil  to 
grind  out  such  ends.  If,  however,  the  link  has  altered  so 
much  as  to  make  the  grinding  a  long  and  tedious  operation, 
it  may  be  opened  by  placing  a  bolt  and  nut  in  such  a  posi- 
tion in  the  slot  that  the  head  of  the  bolt  will  rest  against 
one  side  and  the  end  face  of  the  nut  against  the  other  side 
of  the  slot ;  the  head  of  the  bolt  should  then  be  held  sta- 
tionary with  a  wrench  or  spanner,  and  the  nut,  being 
unscrewed,  will  force  open  the  link.  Another  method  is 
to  take  two  keys,  such  as  connecting-rod  keys,  both  having 
an  equal  amount  of  taper  on  them,  and  place  them  in  the 
slot  of  the  link  with  their  edges  bearing  against  each,  and 
with  the  heads  of  the  keys  on  opposite  sides  of  the  link. 
The  operation  is  to  place  a  hammer  against  the  head  of 
one  key,  to  prevent  it  from  driving  out  of  the  link,  and  to 
drive  in  the  other  key.  The  advantage  of  this  method  over 
the  screw  and  nut  is  this :  The  link  will  spring  considerably 
before  it  will  alter  its  form,  so  that,  when  applying  the 
bolt  and  nut,  it  is  difficult,  in  the  second  operation  (pro- 


288  COMPLETE  PRACTICAL  MACHINIST. 

viding  the  first  has  not  effected  the  desired  opening  of  the 
link),  to  find  exactly  how  much  to  unscrew  the  nut.  In  using 
the  keys,  however,  lines  may  be  drawn  across  the  keys  to 
denote  exactly  how  far  they  were  driven  in  during  the  first 
operation,  which  lines  will  guide  the  judgment  as  to  how 
far  to  drive  them  in  the  second  operation.  If  a  link  opens, 
that  is,  if  the  slot  becomes  wider  during  the  process  of 
hardening,  it  may  be  closed  by  clamping,  or  even  by  a 
strong  vise. 

FITTING   CYLINDERS. 

A  casual  cylinder  or  pair  of  cylinders  (there  being  no 
templates  for  marking  the  holes,  etc.)  should  be  fitted  up 
as  follows  :  If  that  part  of  the  cylinder  cover  which  fits  into 
the  cylinder  has  a  portion  cut  away  to  give  room  for  the 
steam  to  enter  (as  is  usually  the  case),  mark  a  line  across 
the  inside  flange  of  the  cover,  parallel  to  the  part  cut  away, 
and  then  scribe  each  end  of  the  line  across  the  edge  of  the 
flange.  Then  mark  a  similar  line  across  the  cylinder  end, 
parallel  to  the  steam  port  where  it  enters  the  cylinder,  and 
scribe  each  end  of  this  line  across  the  cylinder  flange,  so 
that,  when  the  cylinder  cover  is  placed  into  the  cylinder 
and  the  lines  on  the  flanges  of  the  cylinder  and  the  cover 
are  placed  parallel  to  each  other,  the  piece  cut  away  on  the 
cover  will  stand  exactly  opposite  to  the  steam  port,  as  it  is 
intended  to  do.  The  cover  may  then  be  clamped  to  the 
cylinder,  and  holes  of  the  requisite  size  for  the  tap  (the 
tapping  holes,  as  they  are  commonly  called)  may  be 
drilled  through  the  cover  and  the  requisite  depth  into 
the  cylinder  at  the  same  time.  Concerning  the  correct 
size  of  a  tapping  hole  in  cast-iron,  as  compared  to  the 
tap,  there  is  much  difference  of  opinion  and  practice.  On 
the  one  hand,  it  is  claimed  that  the  size  of  the  tapping  hole 
should  be  such  as  to  permit  of  a  full  thread  when  it  is 
tapped  ;  on  the  other  hand,  it  is  claimed  that  two-thirds  or 
even  one-half  of  a  full  thread  is  all  that  is  necessary  in 
holes  in  cast-iron,  because  such  a  thread  is,  it  is  claimed, 


VISE-WORK—FITTING    CYLINDERS.  289 

equally  as  strong  as  a  full  one,  and  much  easier  to  tap.  In 
cases  where  it  is  not  necessary  for  the  thread  to  be  steam- 
tight  and  where  the  length  of  the  thread  is  greater  by  at 
least  J  inch  than  the  diameter  of  the  bolt  or  stud,  three- 
quarters  of  a  full  thread  is  all  that  is  necessary,  and  can 
be  tapped  with  much  less  labor  than  would  be  the  case  if 
the  hole  was  small  enough  to  admit  of  a  full  thread, 
partly  because  of  the  diminished  duty  performed  by  the 
tap,  and  partly  because  the  oil  (which  should  always  be 
freely  supplied  to  a  tap)  obtains  so  much  more  free  access 
to  the  cutting  edges  of  the  tap.  If  a  long  tap  is  employed 
to  cut  a  three-quarter  full  thread,  it  may  be  wound  con- 
tinuously down  the  hole,  without  requiring  to  be  turned 
backwards  at  every  revolution  or  so  of  the  tap,  to  free  it 
from  the  tap  cuttings  or  shavings,  as  would  be  necessary 
in  case  a  full  thread  was  being  cut.  The  saving  of  time 
in  consequence  of  this  advantage  is  equal  to  at  least  50 
per  cent,  in  favor  of  the  three  quarter  full  thread. 

The  cylinder  covers  must,  after  being  drilled,  as  above, 
be  taken  from  the  cylinder,  and  the  clearing  drill  put 
through  the  holes  already  drilled  so  that  they  will  admit 
the  bolts  or  studs,  the  clearing  holes  being  made  -/g  inch 
larger  than  the  diameter  of  the  bolts  or  studs.  The  steam- 
chests  may  be  either  clamped  to  the  cylinder,  and  tapping 
holes  chilled  through  it  and  the  cylinder  (the  same  as  done 
in  the  case  of  the  covers)  or  it  may  have  its  clearing  holes 
drilled  in  it  while  so  clamped,  care  being  taken  to  let  the 
point  of  the  drill  enter  deep  enough  to  pass  completely 
through  the  steam-chest,  and  into  the  cylinder  deep  enough 
to  cut  or  drill  a  countersink  nearly  or  quite  equal  to  the 
diameter  of  the  drill.  If,  however,  the  steam-chest  is 
already  drilled,  it  may  be  set.  upon  the  cylinder,  and  the 
holes  marked  on  the  cylinder  face  by  a  scriber,  or  by  tho 
end  of  a  piece  of  wood  or  of  a  bolt,  which  end  may  be 
made  either  conical  or  flat  for  the  purpose,  marking  being 
placed  upon  it ;  so  that,  by  putting  it  through  the  hole  of 
25 


290 


COMPLETE  PRACTICAL  MACHINIST. 


the  chest,  permitting  it  to  rest  upon  the  cylinder  face  (which 
may  be  chalked  so  as  to  show  the  marks  plainly),  and  then 
revolving  it  with  the  hand,  it  will  mark  the  cylinder  face. 
This  plan  is  generally  resorted  to  when  the  holes  in  the 
chest  are  too  deep  to  permit  of  being  scribed.  To  true  the 
back  face,  round  a  hole  against  which  face  the  bolt  head  or 
the  face  of  the  nut  may  bed  (in  cases  where  such  facing 
cannot  be  done  by  a  pin  countersink  or  a  cutter  used  in  a 
machine),  the  appliance  shown  in  Fig.  254  may  be  em- 
ployed, a  being  a  pin  provided  with  a  slot  at  one  end  to 


admit  the  cutter  B,  which  is  held  fast  by  the  key  C,  a'nd  is 
also  provided  with  a  square  end  /,  by  which  it  may  be 
turned  or  revolved  by  means  of  a  wrench,  and  with  a 
thread  to  receive  the  nut  E,  d  being  a  washer ;  so"  that,  by 
screwing  up  the  nut  E,  the  cutting  edges  of  the  cutter  are 
forced  against  the  cylinder  g,  and  will,  when  revolved,  cut 
the  face  against  which  they  are  forced,  true  with  the  hole 
in  the  cylinder  through  which  the  pin  a  is  passed. 

To  fit  the  cylinder  cover  joint,  put  marking  on  the  joint 
face  of  the  cover ;  put  the  cover  into  its  place  on  the  cylin- 
der face  ;  then,  in  order  to  discover  how  much  the  faces  are 
out  of  true,  strike  the  outside  of  the  cover  on  one  side  of  its 


VISE  WORK— FITTING   CYLINDERS.  291 

diameter,  and  then  the  other,  alternately,  with  the  fist; 
and  if  the  faces  at  any  point  are  open,  they  will  strike  each 
other  with  a  blow  the  sound  of  which  will  clearly  indicate 
to  what  extent  they  are  out  of  true  ;  if  much,  the  cover  may 
be  removed  and  the  high  parts  rough-filed  to  any  extent  the 
judgment  may  indicate;  if,  however,  when  the  cover  is  struck, 
the  faces  give  no  sound  of  striking,  smooth  filing  will  an- 
swer. When  the  faces  mark  nearly  all  over,  the  high  spots 
may  be  eased  with  the  scraper  until  the  surfaces  are  suffi- 
ciently close  that  a  light  coating  of  marking  will  mark  them 
all  over,  when  they  may  be  ground  together  as  follows:  Place 
on  the  cylinder  face  grain  emery  and  oil,  and  then  put  the 
cover  on.  Fasten  to  the  cover  a  lever,  and  then  place  suf- 
ficient weight  upon  the  cover  to  leave  it  capable  of  being 
conveniently  moved  by  means  of  the  lever  (which  should 
project  on  both  sides  of  the  cover).  The  cover  must  not  be 
revolved  all  in  one  direction,  or  the  emery  will  cut  grooves 
in  the  face,  but  must  be  moved  back  and  forth  while  it  is 
being  revolved.  When  the  grinding  has  proceeded  until  the 
cover  moves  smoothly  upon  the  cylinder  face,  indicating  that 
the  emery  has  worn  down  and  worked  out  (as  it  will  do) 
from  between  the  faces,  the  cover  may  be  removed  ;  and  if 
the  grinding  appears  equal  and  of  one  shade  of  color  all  over 
the  faces,  the  emery  may  be  wiped  off*  them,  and  the  cover 
replaced  and  revolved  back  and  forth  as  before,  which  will 
cause  the  faces  to  polish  each  other,  removing  all  traces  of 
the  emery,  and  showing  plainly  the  slightest  defect  in  the 
surfaces.  If,  however,  the  first  grinding  is  not  sufficient 
(as  is  generally  the  case),  oil  and  emery  must  be  again 
supplied,  and  the  grinding  continued  as  in  the  first  in- 
stance. The  cover  of  an  18  inch  cylinder,  even  if  it  i? 
much  out,  may  be  made  of  a  steam-tight  fit  by  this  process 
in  about  half  an  hour. 

It  is  obvious  that,  in  the  case  of  a  large  cylinder  cover, 
such  as  are  used  for  marine  purposes,  the  hand  will  not  strike 
a  sufficient  blow  to  indicate  how  much  the  faces,  before 


292  COMPLETE  PRACTICAL  MACHINIST. 

fitting,  are  out  of  true,  ami  a  block  of  wood  and  a  hammer 
must  be  employed  instead. 

The  next  operation  is  to  cut  out  the  cylinder  ports  to 
their  requisite  dimensions. 

In  facing  up  the  valve  faces,  the  surface  plate  may,  in 
like  manner,  be  struck  on  its  opposite  corners,  or  a  pressure 
may  be  placed  on  them  by  the  hands  to  ascertain  if  the  sur- 
face plate  will  rock,  and  to  what  extent.  If  it  rocks  at  all, 
a  rough  file  should  be  employed  to  file  away  the  high  parts 
of  the  face ;  if  it  does  not  rock,  a  smooth  file  should  be 
employed  to  take  out  the  tool  marks,  the  filing  being  con- 
tinued until  a  light  coat  of  marking  on  the  surface  plate 
will  mark  the  cylinder  face  all  over,  when  the  scraper  may 
be  applied  to  finish  it.  The  slide  valve  itself  may  then  be 
surfaced  and  scraped  to  the  surface  plate,  and  then  placed 
upon  the  cylinder  face,  and  the  valve  and  cylinder  face 
scraped  together. 

The  joint  of  the  steam-chest  may  be  made  by  filing  the 
planed  surfaces  to  a  straight  edge,  and  placing  between  the 
chest  and  its  seat  on  the  one  hand,  and  the  cover  and  the 
chest  on  the  other  hand,  a  lining  of  very  thin  softened 
sheet  copper,  which  plan  is  generally  adopted  on  cylinders 
for  locomotives. 

In  cases  where  a  number  of  cylinders  of  similar  sizes  are 
made,  the  whole  of  the  marking  off,  and  much  other  work, 
may  be  saved  by  the  employment  of  gauges,  etc. 

For  drilling  the  cylinder  covers  and  the  tapping  holes 
in  the  cylinder,  the  following  system  is  probably  the  most 
advantageous :  The  flanges  of  the  cylinder  covers  are 
turned  all  of  one  diameter,  and  a  ring  is  made,  the  in- 
side diameter  of  which  is,  say,  an  inch  smaller  than 
ihe  bore  of  the  cylinder  ;  and  its  outside  diameter  is,  say, 
an  inch  larger  than  the  diameter  of  the  cover.  On  the 
outside  of  the  ring  is  a  projecting  flange  which  fits  on  the 
cover,  and  which  is  provided  with  holes,  the  positions  of 
which  correspond  with  the  required  positions  of  the  holes 


VISE- WORK— FITTING    CYLINDERS.  293 

in  the  cover  and  cylinder ;  the  diameter  of  these  holes  (in 
the  ring,  or  template,  as  it  is  termed)  is  at  least  one  quar- 
ter inch  larger  than  the  clearing  holes  in  the  cylinder  are 
required  to  be.  Into  the  holes  of  the  template  are  fitted 
two  bushes,  one  having  in  its  centre  a  hole  of  the  size 
necessary  for  the  tapping  drill,  the  other  a  hole  the  size  of 
the  clearing  drill ;  both  these  bushes  are  provided  with  a 
handle  by  which  to  lift  them  in  and  out  of  the  template, 
and  both  are  hardened  to  prevent  the  drill  from  cutting 
them,  or  the.  borings  of  the  drill  from  gradually  wearing 
their  holes  larger.  The  operation  is  to  place  the  cover  on 
the  cylinder  and  the  template  upon  the  cover,  and  to  clamp 
them  together,  taking  care  that  both  cover  and  template  are 
in  their  proper  positions,  the  latter  having  a  flat  place  or 
deep  line  across  a  segment  of  its  circumference,  which  is 
placed  in  line  with  the  part  cut  away  on  the  inside  of  the 
cover  to  give  free  ingress  to  the  steam,  and  the  cover  being 
placed  in  the  cylinder,  so  that  the  part  so  cut  away  will  be 
opposite  to  the  port  in  the  cylinder,  by  which  means  the 
holes  in  the  covers  will  all  stand  in  the  same  relative  posi- 
tion to  any  definite  part  of  the  cylinder,  as,  say,  to  the  top 
or  bottom,  or  to  the  steam-port,  which  is  sometimes  of 
great  importance  (so  as  to  enable  the  wrench  to  be  applied 
to  some  particular  nut,  and  prevent  the  latter  from  coming 
into  contact  with  a  projecting  part  of  the  frame  or  other 
obstacle).  The  bush,  having  a  hole  in  it  of  the  size  of  the 
clearance  hole,  is  the  one  first  used,  the  drill  (the  clearance 
size)  is  passed  through  the  bush,  which  guides  it  while  it 
drills  through  the  cover,  and  the  point  cuts  a  countersink 
in  the  cylinder  face.  The  clearing  holes  are  drilled  all 
round  the  cover,  and  the  bush,  having  the  tapping  size 
hole  in  it,  is  then  brought  into  requisition,  the  tapping 
drill  being  placed  in  the  drilling  machine,  and  the  tapping 
holes  drilled  in  the  cylinder  flange,  the  bush  serving  as  a 
guide  to  the  drill,,  thus  causing  the  holes  in  the  cover  and 
those  in  the  cylinder  to  be  quite  true  with  each  other.  A 
25 : 


294  COMPLETE  PRACTICAL  MACHINIST. 

similar  template  and  bush  is  provided  for  drilling  the  holes 
in  the  steam-chest  face  on  the  cylinder,  and  in  the  steam- 
chest  itself.  While,  however,  the  cylinder  is  in  position  to 
have  the  holes  for  the  steam-chest  studs  drilled,  the  cylinder 
ports  may  be  cut  as  follows,  which  method  was  introduced 
in  1867,  with  marked  success,  by  Mr.  John  Nichols,  who  was 
then  manager  of  the  Grant  Locomotive  Works  at  Paterson, 
N.  J. :  The  holes  in  the  steam-chest  face  of  the  cylinder 
being  drilled  and  tapped,  a  false  face  or  plate  is  bolted 
thereon,  which  plate  is  provided  with  false  ports  or  slots, 
about  three-eighths  of  an  inch  wider  and  three-fourths  of 
an  inch  longer  than  the  finished  width  and  length  of  the 
steam-ports  in  the  cylinder  (which  excess  in  width  and 
length  is  to  allow  for  the  thickness  of  the  die).  Into 
these  false  ports  or  slots  is  fitted  a  die,  to  slide  (a  good  lit) 
from  end  to  end  of  the  slots.  Through  this  die  is  a  hole 
the  diameter  of  which  is  that  of  the  required  finished 
width  of  the  steam-ports  of  the  cylinder.  Into  the  hole  of 
the  die  is  fitted  a  reamer,  with  cutting  edges  on  its  end 
face  and  running  about  an  inch  up  its  sides,  termina- 
ting in  the  plain  round  parallel  body  of  the  reamer,  whose 
length  is  rather  more  than  the  depth  of  the  die.  The 
operation  is  to  place  the  reamer  in  the  drilling  machine, 
taking  care  that  it  runs  true,  place  the  die  in  one  end  of 
the  port,  and  then  wind  the  reamer  down  through  the  die 
so  that  it  will  cut  its  way  through  the  port  of  the  cylinder 
at  one  end ;  the  spindle  driving  the  drill  is  then  wound 
along.  The  reamer  thus  carries  the  die  with  it,  the  slot  in 
the  false  face  acting  as  a  guide  to  the  die. 

In  the  case  of  the  exhaust  port,  only  one  side  is  cut  out  at 
a  time.  It  is  obvious  that,  in  order  to  perform  the  above 
operation,  the  drilling  machine  must  either  have  a  sliding 
head  or  a  sliding  table,  the  sliding  head  being  preferable. 

The  end  of  the  slot  at  which  the  die  must  be  placed  when 
the  reamer  is  wound  down  through  the  die  and  cylinder  port, 
that  is  to  say,  the  end  of  the  port  at  which  the  op<  ration  oi 


VISE  WORK— FITTING    CYLINDERS.  295 

cutting  it  must  be  commenced,  depends  solely  on  which  side 
of  the  port  in  the  cylinder  requires  most  metal  to  be  cut 
off,  since  the  reamer  or  cutter,  as  it  may  be  more  properly 
termed,  must  cut  underneath  the  heaviest  cut,  so  that  the 
heaviest  cut  will  be  forcing  the  reamer  back.  The  reason 
for  the  necessity  of  observing  these  conditions,  as  to  tlis 
depth  of  cut  and  direction  of  cutter  travel,  is  that  the 
pressure  of  the  cut  upon  the  reamer  is  in  a  direction  to 
force  the  reamer  forward  and  into  its  cut  on  one  side,  and 
backward  and  away  from  its  cut  on  the  other  side,  the 
side  having  the  most  cut  exerting  the  most  pressure.  If, 
therefore,  the  cutter  is  fed  in  such  a  direction  that  this 
pressure  is  the  one  tending  to  force  the  cutter  forward,  the 
cutter  will  spring  forward  a  trifle,  the  teeth  of  the  cutter 
taking  in  consequence  a  deep  cut,  and,  springing  more  as 
the  cut  deepens,  terminate  in  a  pressure  which  breaks  the 
teeth  out  of  the  cutter.  If,  however,  the  side  exerting  the 
most  pressure  upon  the  reamer  is  always  made  the  one 
forcing  the  cutter  back,  by  reason  of  the  direction  in  which 
the  cutter  is  travelled  to  its  cut,  the  reamer  in  springing 
away  from  the  undue  pressure  will  also  spring  away  from 
its  cut,  and  will  not,  therefore,  rip  in  or  break,  as  in  the 
former  case. 

In  cutting  out  the  exhaust  port,  only  one  side,  in  conse- 
quence of  its  extreme  width,  may  be  cut  at  one  operation  ; 
hence  there  are  two  of  the  slots  provided  in  the  false  plate 
or  template  for  the  exhaust  port.  The  cutter  must,  in  this 
case,  perform  its  cut  so  that  the  pressure  of  the  cut  is  in  a 
direction  to  force  the  cutter  backwards  from  its  cut.  The 
time  required  to  cut  out  the  ports  of  an  ordinary  locomo- 
tive cylinder,  by  the  above  appliance,  is  thirty  minutes, 
the  operation  making  them  as  true,  parallel,  and  square  as 
can  possibly  be  desired. 

In  order  to  tap  the  holes  in  the  cylinder  heads  and 
steam-chest  seat  on  the  cylinder  true,  without  requiring 
the  workman  to  apply  the  square,  a  l'»ng  tap  and  a  guide 


296  COMPLETE  PRACTICAL  MACHINIST. 

is  employed  for  holding  the  guide  to  the  cylinder  face.  If 
the  end  cylinder  faces  have  a  projecting  ring  on  them 
(so  as  to  leave  a  small  surface  to  make  the  joint),  the  guide 
may  be  cut  away  on  its  bottom  face  to  fit  the  projection, 
so  that  if  the  guide  is  held  against  the  projection,  while 
the  guide  is  bolted  fast,  the  hole  in  the  guide  through 
which  the  tap  passes  will  stand  true  (both  ways)  of  itself, 
to  the  hole  to  be  tapped  in  the  cylinder.  In  the  case, 
however,  of  there  being  no  projection  of  the  kind  men- 
tioned, as,  for  instance,  when  tapping  the  holes  in  the  seat 
for  the  steam-chest,  the  guide  will  require  adjusting  side- 
ways, by  the  eye.  The  distance,  however,  of  the  holes  in 
the  guide  being  the  same  from  centre  to  centre  as  the  dis- 
tance from  centre  to  centre  of  the  holes  to  be  tapped, 
insures,  without  any  setting,  that  the  holes  tapped  are 
true  with  each  other  one  way. 

The  saving  of  time  and  labor  effected  by  means  of 
the  employment  of  this  system  and  its  appliances  is  much 
greater  than  might  be  supposed  at  first  sight;  it  may, 
however,  be  appreciated  when  it  is  stated  that,  under  it, 
three  pairs  of  locomotive  cylinders  have  been  fitted  up  by 
one  skilled  workman  and  one  assistant  in  seven  and  a  half 
days,  the  work  done  to  each  pair  being  the  holes,  amount- 
ing to  200,  drilled,  and  those  for  the  cylinder  covers,  cyl- 
inder cocks,  steam-chests,  steam-pipes,  and  exhaust-pipes, 
tapped  ;  the  steam  and  exhaust  ports  cut  out,  and  the  faces 
and  those  of  the  slide  valves  scraped  up,  the  cylinder  end 
and  cover  faces  filed,  scraped,  and  ground  up  steamtight, 
the  steam-chest  seat  faces  filed  up  true  to  a  straight  edge, 
the  seat  for  the  steam  and  exhaust  ports  faced  out  with  the 
cutter,  all  necessary  bolts  and  studs  put  in,  the  cylinders 
bolted  together,  their  bores  being  set  true  with  each  other, 
and  the  whole  turned  out  so  that  the  cylinders  were  com- 
plete and  ready  to  bolt  to  the  engine  frames. 

For  screwing  the  studs  into  a  cylinder  the  following 
tool  should  be  used  :  a  piece  of  iron,  say  four  inches  long, 


VISE-  WOllK—SCRAPiyO.  217 

should  have  one  end  cut  square  for  ti  wrench  to  fit,  and  in 
the  other  end  a  hole,  tapped  clear  down  to  its  bottom  and 
fitting  the  thread  of  the  stud  loosely  ;  the  stud  will  then 
bottom  in  it  when  being  screwed  in,  while,  when  the  stuif 
is  home  in  the  cylinder,  the  tool  will  leave  it  easily  witl/ 
out  unscrewing  it  again. 

SCRAPED    SURFACES. 

There  are  many  who  believe  that  surfaces  properly 
planed  are  sufficiently  true  for  all  ordinary  practical  pur- 
poses ;  but  if  those  persons  were  to  apply  a  surface  plate  to 
a  well-planed  surface  a  foot  square,  or  to  a  common  con- 
necting rod,  key  and  gib,  as  they  usually  leave  the  planer, 
they  would  be  effectually  cured  of  the  fallacy  of  their 
opinion  upon  this  matter. 

It  is  impossible  to  hold  a  piece  of  work  sufficiently  firm 
that  it  can  be  cut  by  a  machine  tool  without  springing  it ; 
and  though  in  stout  work  having  a  fair  bedding  beneath 
the  clamping  bolts,  and  in  work  in  which  the  pressure 
referred  to  is  sustained  in  a  direction  to  directly  compress 
the  metal  of  the  work,  the  amount  of  this  spring  may  be 
almost  imperceptible,  still,  in  light  and  in  a  great  deal  of 
other  work,  the  amount  of  spring  due  to  the  pressure  of 
holding  the  work  is  sufficiently  great  to  throw  it  out  of  true. 
Another  of  the  reasons  for  the  necessity  of  using  surface 
plates  is,  that  all  work  alters  its  form  from  having  its  sur- 
face skin  removed,  as  will  be  hereafter  explained.  All 
working  flat  surfaces  should  be  surfaced  to  a  surface  plate, 
whether  they  are  intended  to  be  finished  with  a  file  or  a 
semper.  Scrapers  are  not  intended  for  use  as  tools  to  take 
off  a  quantity  of  metal,  but  for  the  purpose  of  making  the 
work  very  true,  being  used  by  itself  or  in  conjunction  with 
a  file  to  ease  away  the  high  spots ;  not  because  it  is  impos- 
sible with  a  file  of  even  sweep  and  flat  cross  surface  to  file 
true,  but  because  it  is  a  quicker  and  easier  method  of 
obtaining  a  flat  surface,  and  one  that  is  absolutely  indis- 


298  COMPLETE  PRACTICAL  MACHINIST. 

pensable  to  fine  work  if  the  file  has  warped  to  a  sensible 
degree  in  the  hardening.  If,  after  a  piece  of  work  has 
been  planed  and  the  surface  plate  has  been  applied, 
it  is  found  that  the  surface  is  somewhat  out  of  true,  as  is 
generally  the  case,  it  is  better  to  file  the  work  until  the 
surface  is  true,  which  process  will  be  quicker  than  scraping 
from  the  commencement. 

It  is  useless  to  apply  a  scraper  promiscuously  over  a 
surface  for  the  purpose  of  making  it  appear  smooth ;  for  a 
surface  can  be  got  up,  so  far  as  smoothness  is  concerned, 
far  better  with  a  file  and  emery  paper  than  it  can  be  with 
a  scraper.  Fig.  A  represents  a  surface  finished  by  a  file 
and  emery  paper,  the  surface  being  so  fine  that  even 
common  paper  will  scratch  it. 

Fig.  A. 


The  proper  method  of  procedure  in  scraping  a  flat  sur- 
face is  to  first  go  all  over  it,  leaving  the  scraper  marks  as 
shown  in  Fig.  B. 

The  second  time  of  going  over  the  surface  should  leave 
the  marks  as  shown  in  Fig.  C ;  while  the  surface  will 
appear  after  the  third  scraping  as  in  Fig.  D. 

After  each  scraping  we  apply  the  surface  plate  and  rub 
it  well  over  the  work  to  mark  it,  giving  the  surface  of  the 
plate  a  barely  peiiceptible  coat  of  marking,  and  distributing 
the  same  evenly  all  over  with  the  palm  of  the  hand,  so  as 
to  detect  any  grit  that  may  chance  to  have  got  into  the 


VISE-  WORK— SCRAPING. 


299 


marking.   A  piece  of  old  rag  should  "be  used  for  wiping  the 
surfaces  clean  (which  is  better  than   either  new  rag  or 

Fig.  B. 


Fig.  C. 


waste)  and  great  care  should  be  taken  that  the  surfaces 
have  no  dust  or  grit  upon  them,  or  it  will  scratch  the  sur- 


300  COMPLETE  PRACTICAL 

faces.  The  surface  plate  is  made  to  mark  the  work  hy 
being  rubbed  back  and  forth  upon  it,  or,  if  the  work  is 
small,  it  may  be  taken  from  the  vise  and  rubbed  upon  the 
face  of  the  surface  plate.  In  either  case,  the  high  spots 
upon  the  face  of  the  work  will  become  very  dark,  or,  if  the 
amount  of  marking  applied  was  barely  sufficient  to  dull 
the  surface  of  the  plate,  the  marks  will  be  almost  black  and 
will,  b}r  continuous  rubbing  on  the  plate,  become  bright. 
Here  we  may  observe  that  small  work  applied  to  the 

Fig.  D. 


plate  should  be  rubbed  at  the  corners  and  toward  the 
outer  edges  of  the  plate  so  as  to  keep  the  wear  of  the 
latter  as  even  as  possible,  since  the  middle  of  the  surface 
of  the  plate  generally  suffers  the  most  from  use,  becoming 
in  time  hollow. 

The  harder  the  plate  bears  upon  the  work  the  darker 
the  spots,  where  it  touches,  will  appear ;  so  that  the  darker 
the  spots  the  heavier  the  scraping  should  be  performed. 
It  will  be  noted  that  the  scraper  marks  are  much  smaller 
and  finer  at  and  during  the  last  scrapings,  and  it  may  be 


VISE- WORK— MAKING  SURFACE  PLATES.      301 

here  remarked  that  the  scrapings  are  taken  very  light 
and  in  a  direction  lengthwise  of  the  surface  plate  marks 
during  the  finishing  process. 

The  best  form  of  scraper  is  that  shown  in  Fig.  E,  which 

should  be  ground  down  so  that  the  cutting  edge  docs  net 

Fig.  E. 


stand  more  than  a  quarter  of  an  inch  from  the  body  of  the 
tool  during  the  finishing  process  ;  for  the  edge  will  not  cut 
so  smoothly  if  tlu  cutting  end  and  edge  is  bent  far  out. 
After  the  scraper  is  ground,  it  should  be  carefully  oil-stoned 
to  a  smooth  edge.  For  use  upon  brass,  wrought-iron  and 
steel,  the  cutting  edge  should  be  kept  moistened  with  water. 

TO   MAKE   A   SURFACE   PLATE. 

To  obtain  a  true  surface  plate  we  must  first  get  up 
three  plates,  which  we  will  term  numbers  1,  2  and  3. 

We  take  No.  1,  and  placing  a  true  straight  edge 
across  it  we  take  one  end  of  the  straight  edge,  between  the 
finger  and  thumb,  and  taking  care  not  to  place  any  ver- 
tical pressure  upon  it,  we  move  it  sideways  back  and  forth 
about  an  inch,  to  see  where  on  the  plate  the  fulcrum  of  its 
movement  takes  place.  If  the  centre  of  its  movement  is 
at  the  centre  of  the  plate,  then  the  surface  of  the  plate  is 
rounding — that  is,  highest  in  the  middle.  If  the  straight 
edge  moves  on  the  plate,  first,  the  most  at  one  end,  and  then 
the  most  at  the  other  end,  it  demonstrates  that  the  straight 
edge  takes  its  fulcrum  of  movement  towards  the  edges  of 
the  plate,  and  hence  that  the  latter  is  hollow.  If,  however, 
the  straight  edge  moves  with  a  shuffling  movement,  it 
denotes  that  the  plate  is  neither  rounding  nor  hollow. 
The  surface,  however,  may  nevertheless  be  atwist  and 
the  straight  edge  will  not  detect  it,  unless  two  are  used — 
being  placed  parallel  to  each  other,  one  at  the  opposite 
side  of  the  plate  to  the  other — when,  if  the  straight  edges 
26 


302  COMPLETE  PRACTICAL  MACHINIST. 

are  sufficiently  long,  the  eye,  directed  across  the  upper 
edges  of  the  straight  edges,  looking  at  them  sideways,  will 
readily  detect  any  twist.  Having  levelled  Nos.  1  and 
2  as  near  as  possible  by  the  straight  edge,  we  place  mark- 
ing on  one  of  them  and  then  rub  their  surfaces  well  to- 
gether, to  mark  them,  and  then  proceed  to  scrape  them 
until  they  fit  together.  We  should,  however,  when  putting 
their  faces  together  for  the  first  time,  strike  the  back  of  the 
top  plate  a  sharp  blow  at  each  corner  with  the  closed  hand, 
and  if  the  surfaces  are  atwist  at  all,  a  blow  distinctly 
heard  will  be  given  by  the  top  plate  to  the  bottom  one ; 
the  degree  of  loudness  of  the  blow  will  also  denote  how 
much  the  surfaces  are  out  of  true.  It  may  be  thought  that 
the  surfaces,  being  planed,  cannot  well  be  atwist.  Such, 
however,  is  not  the  case,  nor  is  the  twist  due  to  the  planing 
but  to  the  alteration  of  form  which  takes  place  in  the  work, 
by  reason  of  the  tension  of  the  skin  upon  the  face  having 
been  removed.  This  alteration  of  form  may  be  reduced  to  a 
minimum  by  slacking  back  the  bolts,  plates  or  jaws,  hold- 
ing the  work  in  the  planer,  previous  to  taking  the  last  cut 
in  the  planer,  since  the  last  cut  being  a  light  one,  not  much 

pressure   is  required   to  hold 
Fi9:  F'  the  work. 

Having  scraped  Nos.  1  and 
2  together,  we  introduce  No.  3 
I  and  scrape  it  to  fit  No.  2,  not 
'  scraping  the  latter  at  all.  We 
next  try  Nos.  1  and  3  together, 
and  if  they  show  each  other  to 
be  rounding,  it  is  proof  that 
No.  1  is  rounding  to  one-half 
the  amount  of  difference  be- 
tween it  and  No.  3  as  shown 
in  Fig.  F. ;  from  which  it  will 
be  perceived  that  the  two 
nearest  together  faces  of  1 


3 


VISE  WORK— MAKING   SURFACE  PLATES.      303 

and  2  may  fit  together,  one  being  rounded  and  the  other 
hollow.  No.  2  may  then  be  taken  as  a  gauge  whereby  to 
fit  No.  3.  But  if  we  then  take  Nos.  1  and  3,  and  try  them 
together,  they  will  disagree  to  twice  the  amount  that  each 
of  them  separately  is  out — that  is  to  say,  twice  the  amount 
that  No.  1  varied  from  being  a  true  flat  surface. 

We  next  scrape  Nos.  1  and  3  together,  taking  off,  as  nearly 
as  our  judgmsnt  dictates,  an  equal  amount  off  each  with 
the  scraper,  and  this  being  complete,  we  scrape  No.  2  to 
No.  1,  and  then  No.  3  to  No.  2,  finally  bringing  back  No. 
3  to  No.  1,  as  a  test,  scraping  them  together,  taking  an 
equal  amount  off  each,  and  when  they  fit  perfectly  we  fit  2 
again  to  1,  and  3  again  to  2,  continuing  the  whole  operation 
until  all  three  plates  fit,  each  the  others,  perfectly. 

Here,  however,  we  may  note  as  follows :  the  three  plates 
being  of  the  same  size,  as  they  should  be,  and  it  being 
necessary  to  rub  their  faces  together  in  order  to  mark 
where  they  touch  together,  the  abrasion  of  one  face  against 
the  other,  and  therefore  the  marks,  will  not  be  equal. 
Thus,  in  Fig.  G,  plate  1  being  moved  forward,  that  part 

Fig.  G. 
3 


of  its  surface  overlapping  and  denoted  by  C,  and  that  part 
of  plate  2  denoted  by  B,  are  not  in  contact  with  a  surface, 
and  are  not,  therefore,  being  marked  by  the  movement, 
whereas  the  whole  of  the  rest  of  the  surfaces  of  the  two 
plates  are  in  contact,  and  are  therefore  marking  each  other 
during  the  whole  of  the  movement,  the  consequence  being 
that  those  parts  of  the  surfaces  which  overlap  mark  morf 
lightly  in  proportion  to  the  amount  of  their  bearing  than 


304  COMPLETE  PRACTICAL  MACHINIST. 

the  rest  of  the  surfaces,  and  since  it  is  the  lightness  or 
heaviness  of  the  marks  which  determine  how  much  the 
parts  of  contact  must  be  eased  by  the  scraper,  it  becomes 
evident  that  a  surface  plate  cannot  be  made  true  to  the 
highest  practical  attainable  degree,  unless,  having  finished 
the  three  plates,  we  introduce  a  fourth,  whose  size  shall  be 
sufficiently  smaller  that  it  can  be  rubbed  back  and  forth 
upon  the  plate  or  plates  by  which  it  is  surfaced  without 
overlapping  at  all.  The  feet  upon  which  a  surface  plate 
rests  should  be  planed  true,  and  the  plate  resting  upon  the 
bench  should  rest  equally  upon  all  of  the  feet,  otherwise 
the  plate  will  deflect  from  its  own  weight,  the  amount  of 
the  deflection  making  a  practical  difference  in  a  large 
plate. 

TO    CUT   HAED   SAW    BLADES. 

Mark  out  on  the  saw  blade  the  article  you  require  to  cut 
from  it  and  ceutre-punch  it  lightly  all  along  the  lines, 
going  over  and  over  it  until  the  centre-punch  marks,  which 
should  not  be  more  than  -Jg  inch  apart,  are  nearly  through 
the  blade ;  then  take  a  hard  chisel  and  nick  between  and 
along  the  centre-punch  marks.  Then  reverse  the  saw 
blade,  and  centre-punch  from  the  other  side,  and  the  blade 
will  cut  to  almost  any  shape  without  splitting. 

Keys  should  be  made  a  snug  fit  and  parallel  on  the  sides, 
having  taper  on  the  top  and  bottom  only.  They  should  be 
fitted  to  bear  even  all  over,  or  they  spring  the  work  out  of 
true.  A  very  light  coat  of  marking  should  be  used  in 
fitting  them,  and  they  should  be  driven  in  and  out  lightly. 

TO   REFIT    LEAKY    PLUGS   TO   THEIR   COCKS. 

When  a  cock  leaks,  be  it  large  or  small,  it  should  be 
refitted  as  follows,  which  will  take  less  time  than  it  would 
to  ream  or  bore  out  the  cock  or  to  turn  the  plug,  unless  the 
latter  be  very  much  worn  indeed,  while  in  either  case  the 
plug  will  last  much  longer  if  refitted,  as  hereinafter  directed, 
because  less  metal  will  be  taken  off  it  in  the  refitting. 


VISE- WORK— COCKS  AND  PLUGS.  305 

After  removing  the  plug  from  the  cock,  remove  the 
scale  or  dirt  which  will  sometimes  be  found  on  the  larger 
end,  and  lightly  draw-file,  with  a  smooth  file,  the  plug  all 
over  from  end  to  end.  If  there  is  a  shoulder  worn  by  the 
cock  at  the  large  end  of  the  plug,  file  the  shoulder  off  even 
and  level.  Then  carefully  clean  out  the  inside  of  the  cock, 
and  apply  a  very  light  coat  of  red  marking  to  the  plug, 
and  putting  it  into  the  cock  press  it  firmly  to  its  seat, 
moving  it  back  and  forth  part  of  a  revolution ;  then,  while 
it  is  firmly  home  to  its  seat,  take  hold  of  the  handle  end 
of  the  plug,  and  pressing  it  back  and  forth  at  a  right  angle 
to  its  length,  note  if  the  front  or  back  end  moves  in  the 
cock ;  if  it  moves  at  the  front  or  large  end,  it  shows  that 
the  plug  is  binding  at  the  small  end,  while  if  it  moves  at 
the  back  or  small  end,  it  demonstrates  that  it  binds  at  the 
front  or  large  end.  In  either  case,  the  amount  of  move- 
ment is  a  guide  as  to  the  quantity  of  metal  to  be  taken  oft' 
the  plug  at  the  requisite  end  to  make  it  fit  the  cock  along 
the  whole  length  of  its  taper  bore.  The  red  marking  re- 
ferred to  is  dry  Venetian  red  and  lubricating  oil,  mixed 
thickly,  a  barely  perceptible  coating  being  sufficient. 

If  the  plug  shows  a  good  deal  of  movement  whon  tested 
as  above,  it  will  be  economical  to  take  it  to  a  lathe,  and, 
being  careful  to  set  the  taper  as  required,  take  a  light  cut 
over  it.  Supposing,  however,  there  is  no  lathe  at  hand,  or 
that  it  is  required  to  do  the  job  by  hand,  which  is,  in  a 
majority  of  cases,  the  best  method,  the  end  of  the  cock 
bearing  against  the  plug  must  be  smooth  filed,  first  moving 
the  file  round  the  circumference,  and  then  draw-filing; 
taking  care  to  take  most  off  at  the  end  of  the  plug,  and 
less  and  less  as  the  other  end  of  the  plug  is  approached. 
The  plug  should  then  be  tried  in  the  cock  again,  according 
to  the  instructions  already  given,  and  the  filing  and  testing 
process  continued  until  the  plug  fits  perfectly  in  the  cock. 
In  trying  the  plug  to  the  cock,  it  will  not  do  to  revolve  tho 
plug  continuously  in  one  direction,  for  that  would  cut  rings 
20 


306  COMPLETE  PRACTICAL  MACHINIST. 

in  both  the  cock  and  the  plug,  and  spoil  the  job ;  the  proper 
plan  is  to  move  the  plug  back  and  forth  at  the  same  time 
that  it  is  being  slowly  revolved.  As  soon  as  the  plug  fits 
the  cock  from  end  to  end,  we  may  test  the  cock  to  see  if  it 
is  oval  or  out  of  round,  as  follows :  First  give  it  a  very 
light  coat  of  red  marking,  just  sufficient,  in  fact,  to  well 
dull  the  surface,  and  then  insert  the  plug,  press  it  firmly 
home,  and  revolve  it  as  above  directed ;  then  remove  the 
plug,  and  where  the  plug  has  been  bearing  against  the  sur- 
face of  the  cock,  the  latter  will  appear  bright.  If,  then,  the 
bore  of  the  cock  appears  to  be  much  oval,  which  will  be 
the  case  if  the  amount  of  surface  appearing  bright  is  small, 
and  on  opposite  sides  of  the  diameter  of  the  bore,  these 
bright  spots  may  be  removed  with  the  half-round  scraper. 
Having  eased  off  the  high  spots  as  much  as  deemed  suffi- 
cient, the  cock  should  be  carefully  cleaned  out  (for  if  any 
metal  scrapings  remain  they  will  cut  grooves  in  the  plug\ 
and  the  red  marking  reapplied,  after  which  the  plug  may 
be  again  applied.  If  the  plug  has  required  much  scraping, 
it  will  pay  to  take  a  half-round  smooth  file  that  is  well 
rounding  lengthwise  of  its  half  round  side,  so  that  it  will 
only  bear  upon  the  particular  teeth  required  to  cut,  and 
selecting  the  highest  spot  on  the  file,  by  looking  down  its 
length,  apply  that  spot  to  the  part  of  the  bore  of  the  cock 
that  has  been  scraped,  draw-filing  it  sufficient  to  nearly 
efface  the  scraper-marks.  The  process  of, scraping  and 
draw-filing  should  be  continued  until  the  cock  shows  that 
it  bears  about  evenly  all  over  its  bore,  when  both  the  plug 
and  the  cock  will  be  ready  for  grinding. 

Here,  however,  it  may  be  as  well  to  remark  that  in  the 
case  of  large  cocks  we  may  save  a  little  time  and  insure  a 
good  fit  by  pursuing  the  following  course,  and  for  the 
given  reasons.  If  a  barrel  bears  all  around  its  water-way 
only  for  a  distance  equal  to  about  fa  of  the  circumference 
of  the  bore,  and  the  plug  is  true,  the  cock  will  be  tight, 
the  objection  being  that  it  has  an  insufficiency  of  wearing 


VISE 'WORK—  COCKS  AND  PLUGS.  307 

surface.  It  will,  however,  in  such  case  wear  better  as  the 
wearing  proceeds.  There  is  perhaps  the  further  objection 
that  so  small  an  amount  of  wearing  surface  may  cause  it 
to  abrade.  This,  however,  has  nothing  to  do  with  our 
present  purpose,  which  is  to  save  time  in  the  grinding, 
insure  a  good  fit,  and,  at  the  same  time,  ample  wearing 
surface.  Our  plug  and  barrel  being  fitted  as  directed,  we 
may  take  a  smooth  file  and  ease  very  lightly  away  all 
parts  of  the  barrel,  save  and  except  to  within  say  I  inch 
around  the  water  or  steam  way.  The  amount  taken  oif 
must  be  very  small — indeed,  just  sufficient,  in  fact,  to  ease 
it  from  bearing  hard  against  the  plug,  and  the  result  will' 
be  that  the  grinding  will  bed  the  barrel  all  over  to  the 
plug,  and  insure  that  the  metal  around  the  water  or  steam- 
way  on  the  barrel  shall  be  a  good  fit,  and  hence  that  the 
cock  be  tight.  In  the  case  of  large  cocks,  the  barrel  and 
the  plug  should  stand  vertical  during  both  the  final  trials 
and  the  grinding  process. 

The  best  material  to  use  for  the  grinding  apparatus  is 
the  red  burnt  sand  from  the  core  of  a  brass  casting,  which 
should  be  sifted  through  fine  gauze,  and  riddled  on  the 
work  from  a  box  made  of  say  a  piece  of  1 2  pipe  4  inches 
long,  closed  at  one  end,  and  having  fine  gauze  instead  of  a 
lid.  Both  the  barrel  and  the  plug  should  be  wiped  clean 
and  free  from  filings,  etc.,  before  the  sand  is  applied ;  the 
inside  of  the  barrel  should  be  wetted,  and  the  plug  dipped 
in  water,  the  sand  being  sifted,  a  light  coat,  evenly  over  the 
barrel  and  the  plug.  The  plug  must  then  be  inserted  in 
the  barrel  without  being  revolved  at  all  till  it  is  home  to 
its  seaf,  when  it  should  be  pressed  firmly  homo,  and  operated 
back  and  forth  while  being  slowly  revolted.  It  should 
also  be  occasionally  taken  a  little  way  out  from  the  barrel 
and  immediately  pressed  back  to  its  seat  and  revolved  as 
before,  which  will  spread  the  sand  evenly  over  the  surfaces 
and  prevent  it  from  cutting  rings  in  either  the  barrel  or  the 
plug.  This  process  of  grinding  may  be  repeated,  with  fresh 


308  COMPLETE  PRACTICAL  MACHINIST. 

applications  of  sand,  several  times,  when  the  sand  may  be 
washed  clean  from  the  barrel  and  the  plug,  both  of  them 
wiped  comparatively  dry  and  clean,  and  the  plug  be  rein- 
serted in  the  barrel,  and  revolved,  as  before,  a  few  revolu- 
tions ;  then  take  it  out,  wipe  it  dry,  reinsert  and  revolve  it 
again,  after  which  an  examination  of  the  barrel  and  plug- 
will  disclose  how  closely  they  fit  together,  the  parts  that 
bind  the  hardest  being  of  the  deepest  color.  If,' after  the 
test  made  subsequent  to  the  first  grinding  operation,  the 
plug  does  not  show  to  be  a  good,  even  fit,  it  will  pay  to  ease 
away  the  high  parts  with  a  smooth  file,  and  repeat  after- 
wards the  grinding  and  testing  operations. 

To  finish  the  grinding,  we  proceed  as  follows :  give  the 
plug  a  light  coat  of  sand  and  water,  press  it  firmly  to  its 
seat,  and  move  it  back  and  forth  while  revolving  it,  lift  it 
out  a  little  from  its  seat  at  about  every  fourth  movement, 
and  when  the  sand  has  ground  down  and  worked  out,  re- 
move the  plug,  and  smear  over  it  evenly  with  the  fingers  the 
ground  sand  that  has  accumulated  on  the  ends  of  the  plug 
and  barrel ;  then  replace  it  in  the  barrel,  and  revolve  as 
before  until  the  plug  moves  smoothly  in  the  barrel,  bearing 
in  mind  that  if  at  any  time  the  plug,  while  being  revolved 
in  the  barrel,  makes  a  jarring  or  grating  sound,  it  is  cutting 
or  abrading  from  being  too  dry.  Finally,  wipe  both  the 
barrel  and  the  plug  clean  and  dry,  and  revolve  as  before 
until  the  surfaces  assume  a  rich  brown,  smooth  and  glossy 
appearance,  showing  very  plainly  the  exact  nature  of  the 
fit.  Then  apply  a  little  tallow,  and  the  job  is  complete 
and  perfect. 

REFITTING   WORK    BY   SHRINKING   IT. 

For  closing  long  holes,  boxes,  etc.,  the  water  process  may 
be  employed,  as  represented  in  Fig.  H.  a  a  is  the  section 
of  a  wrought-iron  square  box  or  tube,  which  is  supposed  to 
be  made  red  hot  and  placed  suddenly  in  the  water,  B,  from 
its  end  C  to  the  point  D,  and  held  there  until  the  end 


VISE- WORK— REFITTING    WORK. 


309 


submerged  is  cold;  the  result  is  that  the  metal  in  the 
Water,  from  C  to  D,  contracts  or  shrinks  in  diameter,  and 
compresses  the  hot  metal  immediately  above  the  water-line, 


Fig.  H. 


Fig.  J. 


as  the  small  cone  at  D  denotes.  If,  then,  the  box  or  tubs 
is  slowly  immersed  in  the  water,  this  action  of  compression 
is  carried  all  the  way  up  from  that  point,  and  its  form, 
when  cold,  will  be  as  described  in  Fig.  J,  that  part  from 
C  to  D  maintaining  its  original  size,  and  the  remainder 
being  smaller. 

It  must  then  be  reheated  and  suddenly  immersed  from 
the  end  E  nearly  to  D,  held  there  until  it  is  cold,  and 
then  slowly  lowered  in  the  water,  as  before,  which  will  con- 
tract the  part  from  D  to  C,  making  the  entire  length  paral- 
lel but  smaller,  both  in  diameter  and  bore,  than  before  it 
was  thus  operated  upon. 

Small  holes  to  be  reduced  in  bore  by  this  process  should 
be  filled  with  fire  clay,  and  the  faces  nearly  or  wholly 
covered  with  the  same  substance,  so  that  the  water  will 
first  cool  the  circumference,  and  the  circumference  will,  in 
contracting,  force  inwards  the  metal  round  the  hole,  which 
is  prevented  from  cooling  so  quickly  by  the  clay,  and 


310  COMPLETE  PRACTICAL  MACHINIST. 

therefore  gives  way  to  the  compressing  force  of  the  outside 
and  cooler  metal. 

This  principle  may  be  made  use  of  for  numerous  pur- 
poses, as  for  reducing  diameters  of  the  tires  of  wheels, 
reducing  the  size  of  wrought-irou  bands,  or  for  closing  in 
connecting  rod  straps  to  refit  them  to  the  block  end,  the 
mode  of  operation  for  which  is,  in  the  case  of  a  rod  whose 
strap  is  held  by  bolts  running  through  the  block  and  strap, 
to  bolt  the  strap  on  the  rod  to  prevent  it  from  warping,  to 
then  heat  the  back  of  the  strap,  and  (holding  the  rod  in  a 
vertical  position)  submerge  the  back  of  the  strap  in  water 
to  nearly  one-half  its  thickness. 

If  the  bolts  are  not  worn  in  the  holes,  or  if  the  strap  is 
one  having  a  gib  and  key,  they  may  be  merely  put  into 
their  places  without  placing  the  strap  on  the  rod.  Even  a 
plain  piece  of  iron  shrinks  by  being  heated  and  plunged 
into  water,  but  only  to  a  slight  degree,  and  the  operation 
cannot  be  successfully  repeated.  Eccentric  rods,  which 
require  to  be  shortened,  say  ^  of  an  inch,  may  be  operated 
on  in  this  manner,  in  which  case  care  must  be  taken  to 
immerse  them  evenly  so  as  not  to  warp  them. 

Much  labor  and  expense  may  often  be  saved  by  employ- 
ing the  principles  of  expansion  and  contraction  to  refit 
work.  For  instance,  suppose  a  bolt  has  worn  loose :  the 
bolt  may  be  hardened  by  the  common  prussiate  of  potash 
process,  which  will  cause  it  to  increase  in  size,  both  in 
length  and  diameter.  The  hole  may  be  also  hardened  in 
the  same  way,  which  will  decrease  its  diameter ;  and  if  the 
decrease  is  more  than  necessary,  the  hole  may  be  ground 
or  "  lapped  "  out  by  means  of  a  lap. '  Only  about  g]?  of  an 
inch  of  shrinkage  can  be  obtained  on  a  hole  and  bolt  by 
hardening,  which,  however,  is  highly  advantageous  when 
it  is  sufficient,  because  both  the  hole  and  the  bolt  will  wear 
longer  for  being  hardened. 

Set  screws  should  be  made  of  steel,  the  end  being  cupped 
and  the  thread  at  the  end  being  chamfered  off,  and  that 
end  being  hardened. 


NOTES  ON   VISE-WORK.  311 

To  put  a  fixed  feather  in  a  shaft,  cut  out  the  seat  for  the 
feather  and  then  take  a  chisel-set,  and  bulge  out  the  sides 
of  the  recess.  The  feather  (which  should  have  the  part 
intended  to  be  set  in  the  shaft  slightly  dovetailed,  the  largest 
part  of  the  dovetail  resting  on  the  bottom  of  the  recess) 
should  then  be  put  in  its  place,  and  the  metal  of  the  shaft 
should  be  closed  around  the  feather^  a  set  being  used  for  the 
purpose;  thus  the  feather  will  be  riveted  in  its  place,  while 
the  surface  of  the  shaft  will  retain  its  roundness,  because 
of  the  sides  of  the  recess  having  been  bulged  as  directed. 
After  the  feather  is  fastened,  the  surface  of  the  shaft  may 
be  filed  smooth  and  even. 

Standing  bolts  or  studs  which  are  placed  in  a  position 
liable  to  corrode  them  should  have  the  standing  ends  i 
inch  larger  than  the  nut  end,  and  the  plain  part  should 
be  square.  By  this  means  a  wrench  may  be  applied  to 
extract  them  when  necessary,  and  the  stud  is  not  so  liable 
to  break  off  in  consequence  of  weakness,  at  the  junction  of 
the  thread,  and  the  plain  part  where  the  groove  to  relieve 
the  termination  of  the  thread  is  cut. 

Bolts  that  have  become  corroded  in  their  holes  so  that 
they  are  liable  to  twist  or  break  off  in  extracting  them, 
should  be  well  warmed  by  a  red  hot  nut  or  washer,  because 
the  strength  of  the  stud  increases  by  being  heated  up  to 
about  400°  Fahr.,  and,  therefore,  studs  which  readily  twist 
off  when  cold  will  unscrew  when  heated  to  about  that  tem- 
perature. 

Nuts  upon  standing  bolts  in  the  smoke-boxes  of  locomo- 
tives or  in  similar  positions,  which  have  become  so  corroded 
as  to  endanger  twisting  the  bolt  off,  should  be  cut  through 
with  a  cape  or  cross-cut  chisel,  thus  saving  the  stud  at 
the  expense  of  the  nut.  The  split  must  be  cut  from  the 
outside  end  face  to  the  bedding  face  of  the  nut.  To  ease  a 
nut  that  is  a  little  too  tight  in  the  thread,  screw  it  upon 
the  bolt,  and,  resting  it  upon  a  block  of  iron,  strike  the 
upper  side  with  a  hammer,  turning  the  nut  so  that  not 


813  COMPLETE  PRACTICAL  MACHINIST. 

more  than  two  blows  will  fall  upon  one  face  at  a  time,  and 
striking  light  blows  towards  the  last  part  of  the  operation. 

To  ease  a  nut  that  is  too  tight  to  its  place  to  unscrew,  so 
that  an  ordinary  wrench  will  not  move  it,  strike  a  few 
sharp  blows  on  its  end  face;  then,  holding  a  dull-edged 
chisel  firmly  across  the  chamfer  of  the  nut,  strike  the  chisel- 
head  a  few  sharp  blows.  Another  plan  is  to  put  the  full 
force  of  the  wrench  upon  the  nut,  and  strike  at  the  same 
time  the  nut  a  few  sharp  blows  upon  its  end  face.  If  the 
nut  is  a  large  one,  a  piece  of  tube  applied  to  the  end  of 
the  wrench,  together  with  blows  struck  on  the  end  face, 
will  often  suffice  to  start  the  nut,  especially  if  the  nut  is 
warmed. 

Brass  castings  under  12  inches  in  size  shriuk  about  -| 
inch  to  a  foot  in  cooling  in  the  mould.  Large  castings 
shrink  about  T3g  inch. 

To  prevent  air-holes  in  copper  castings  they  should  be 
moulded  in  green  sand  moulds,  using  as  a  flux  U  Ibs.  of 
zinc  to  every  100  Ibs.  of  copper.  Pure  copper  will  not  cast 
without  honey-combing. 

In  casting  iron  on  wrought-iron  or  steel  spindles,  the 
metal  should  be  poured  endwise  of  the  mould,  letting  the 
cast  metal  cover  the  spindle  an  inch  longer  on  the  top  end 
than  is  necessary.  Thus  the  air-holes,  if  any,  will  form  in 
the  extra  inch  of  length  and  may  be  cut  off  with  it  in  the 
lathe. 

Iron  castings  shrink  in  the  mould  about  fa  of  an  inch  to 
the  foot.  The  shrinkage  sideways  and  endways  of  a  cast- 
ing 4  inches  or  less  in  size  is  compensated  for  by  the  shake 
in  the  sand  given  by  the  moulder  to  the  pattern  in  order 
to  extract  it  from  the  mould. 

In  very  small  castings  requiring  to  be  of  correct  size, 
allowance  should  be  made  in  the  pattern  for  the  shake  of 
the  pattern  of  the  sand,  thus:  A  pattern  to  cast  an  inch 
cube  will  require  to  be  made  -3J2  inch  less  than  an  inch 
endwise  and  sideways. 


VISE-  WORK— JOINTS.  31 3 

STEAM   AND   WATER   JOINTS. 

The  best  joint  of  any  is  the  ground  or  scraped  joint,  but 
as  this  is  for  many  purposes  too  costly,  the  following,  based 
upon  a  lengthy  practical  experience,  will  be  found  re- 
liable: 

In  fitting  flanges  to  boilers  or  flanges  together,  be  careful 
that  the  closest  contact  is  around  the  hole.  From  the  in- 
side of  the  bolt-hole  to  the  outside  of  a  flange  should  be 
eased  away  a  trifle  whenever  the  bolts  are  standing  bolts 
or  are  not  liable  to  leak. 

Red  lead  joints. — Take  white  lead  ground  in  oil,  and 
mix  with  it  dry  red  lead  sufficient  to  make  it  spread  with 
a  steel  blade  without  sticking  to  it.  Thorough  bray  the 
mixture  by  well  hammering  it  with  a  hand  hammer. 

Gauze'  joints  for  high  temperatures  are  easily  made  and 
are  lasting.  Fine  iron  gauze  is  cut  to  entirely  cover  the 
joint,  and  a  coating  of  red  lead  mixed  as  above  is  laid 
over  it.  If  the  surfaces  of  the  joint  are  very  uneven,  the 
gauze  may  be  doubled. 

For  joints  where  hot  or  cold  water  are  concerned  canvas 
or  duck  may  be  used,  having  on  it  a  coating  of  red  lead 
mixed  as  above. 

For  ordinary  joints  combination  rubber  is  an  excellent 
material.  It  consists  of  alternate  layers  of  rubber  and 
canvas.  When  making  such  a  joint,  one  of  the  surfaces  of 
the  rubber  should  be  chalked  to  prevent  the  rubber  from 
tearing' if  it  becomes  necessary  to  break  the  joint. 

Rust  joint. — Iron  turnings  100  Ibs.,  sal  ammonia  I  lb., 
sulphur  £  lb.  If  the  joint  is  required  to  set  very  quick 
add  i  lb.  more  sal  ammonia.  The  whole  should  be 
thoroughly  mixed  and  just  covered  with  water. 

For  very  high  temperatures,  a  dry  heat  asbestos  board, 
soaked  with  thin  red  lead  and  oil,  makes  the  best  joint. 
27 


CHAPTER    XV. 

FITTING   CONNECTING   RODS. 

THE  planing  work  on  a  connecting  rod  being  complete, 
the  first  thing  for  the  fitter  to  do  is  to  mark  off  the  key> 
ways,  the  bolt  holes  (if  there  are  any),  the  holes  for  the  set 
screws,  the  oil  holes,  etc.,  so  as  to  have  the  drilling  com- 
pleted before  the  straps  or  rod  ends  are  filed  up,  because 
drills  leave  a  burr  where  they  come  through  the  metal,  and 
because  the  clamps,  wrhich  hold  the  work  while  it  is  being 
drilled,  are  apt  to  leave  marks  upon  it.  The  holes  should 
then  be  tapped,  when  the  rod  will  be  ready  for  the  file.  The 
faces  of  the  rod  whereon  the  straps  fit  should  then  be  sur- 
faced with  a  surface  plate,  and  made  quite  square  with  the 
broad  faces  of  the  rod,  parallel  crosswise  with  each  other, 
and  a  little  taper  with  each  other  in  the  length.  The  strap 
should  be  made  narrower  between  its  jaws  than  the  width 
of  the  rod  end,  so  as  to  require  to  spring  open  when  placed 
upon  the  rod  end  if  the  brasses  are  not  in  their  places.  The 
inside  faces  of  the  jaws  of  the  strap  must  be  made  quite 
square  with  the  side  faces,  so  that,  when  the  strap  is  placed 
upon  the  rod  end,  the  latter  faces  of  the  strap  will  not 
spring  out  true  with  the  broad  faces  of  the  rod  end.  The 
rod  end  must  have  a  light  coating  of  marking  rubbed  over 
it,  and  the  strap  moved  back  and  forth  on  it,  so  that  the 
rod  end  serves  as  a  gauge  and  surfacing-block  to  the  strap. 

If,  when  the  strap  is  on  its  place,  its  side  faces  are  uneven 

with  the  side  faces  of  the  rod  end,  as  shown  in  Fig.  255 

(which  is  a  sectional  view  of  a  strap  and  rod  end,  a  being 

the  rod  end,  and  B  B  the  jaws  of  the  strap),  either  one  or 

314 


FITTING   CONNECTING  RODS. 


315 


both  of  the  inside  side  faces  of  the  strap  require  filing  in  the 
direction  denoted  by  the  dotted  lines,  because  it  is  only  in 
consequence  of  the  inside  faces  not  being  square 
with  the  outside  faces  that  this  twist  occurs. 
The  key  ways  in  the  strap  and  rod  end  should 
be  filed  out  together,  that  is,  while  the  strap 
is  on  its  place  and  secured  by  being  clamped 
or  bolted.     If  the  strap  is  one  held  to  the  rod 
by  a  gib  and  key,  the  width,  from  the  end  of 
the  rod  to  the  crown  of  the  strap  when  it  is 
placed  in  position  to  cut  or  file  out  the  keyway, 
should  be  that  of  the  extreme  width  of  the 
brasses  when  the  joint  of  the  brasses  is  close, 
less  the  amount  of  taper  there  is  on  the  key. 
The  strap,  after  being  fitted  to  the  rod,  should  be  clamped 
to  the  rod  end,  the  keyway  in  the  strap  and  in  the  rod 
being  placed   fair  with  each  other,  before  the  clamp  is 
tightened,  for  moving  the  strap  after  it  is  clamped  will 
spring  it  out  of  true,  so  that,  when  the  clamp  is  taken  off, 
the  keyways  will  not  be  true  with  each  other  though  they 
were  filed  true.    In  driving  in  the  keys  and  gibs  to  fit  them, 
be  careful  to  put  a  light  coat  of  marking  on  them,  not  only 
to  show  where  they  bind  but  to  prevent  them  from  seizing 
in  the  keyway.     The  key  and  gib  placed  edgewise  together 
should  be  parallel  on  the  outside  edges,  and  the  keyway 
should  b3  parallel  both  edgewise  and  across  its  width.     A 
thin  sheet-iron  gauge  is  better  to  measure  the  thickness  of  the 
keyway  than  inside  calipers  are,  and  the  same  gauge  will 
do  to  plane  the  key  and  gib,  leaving  them  a  little  full  in 
the  thickness.     The  keyways   should   be  surfaced  with  a 
surface  plate,  its  breadth  being  equal  to  that  of  the  gib  and 
key  together  when  the  head  of  the  key  is  even  with  the 
head  of  the  gib  ;  then  when  the  keyway  is  finished,  and  the 
strap  is  placed  in  its  intended  position  on  the  end  of  the 
rod,  the  strap  will  have  moved  back  from  off  the  rod  end 
for  a  distance  equal  to  the  amount  of  the  taper  on  the  key, 


316  COMPLETE  PRACTICAL  MACHINIST. 

so  that  there  will  be  the  requisite  amount  of  draw  on  the 
key  way  of  the  strap  on  the  one  side  and  on  the  keyway  of 
the  rod  on  the  other  side,  while  the  key  will  at  the  same  time 
come  through  the  strap  to  its  required  distance.  The  faces 
of  the  rod  end,  whereon  the  jaws  of  the  strap  fit,  having 
been  made  (as  directed)  a  little  taper,  and  the  strap  allowed 
(as  described)  a  little  spring,  the  rod  end  will  enter  the 
strap  somewhat  easily,  and  tighten  as  it  passes  up  the  strap, 
so  that,  when  quite  up,  the  strap  will  fit  a  little  tighter  than 
it  is  intended,  when  finished,  to  do.  When  the  strap  is 
fitted  and  keyed  to  the  rod,  a  light  cut  should  be  taken  off 
the  faces  of  the  rod  and  strap  while  they  are  together,  the 
bolts  of  a  bolt  rod  being  sufficient  to  hold  the  strap  for  that 
purpose ;  but  in  the  case  of  a  gib  and  key,  a  piece  of  wood 
should  be  placed  between  the  rod  end  and  the  crown  of  the 
strap,  that  is,  in  the  space  intended  to  be  filled  by  the 
brasses,  .and  the  wood  keyed  up  so  as  to  lock  the  strap  on  . 
the  rod  while  the  faces  of  the  rod  and  strap  are  planed. 
This  being  complete,  the  strap  is  rcaay  to  receive  the 
brasses.  The  bottom  or  back  brass  must  be  made  to  a 
tight  fit,  so  as  to  spring  the  strap  open  sufficiently  to  make 
it  fit  the  rod  end  as  easily  as  required  ;  thus  both  the  brass 
and  the  strap  will  be  closely  fitted.  The  top  brass  must  be 
fitted  to  the  strap  while  the  bottom  brass  is  in  its  place  in 
the  strap,  and  must  be  made  to  fit  the  strap  without  being 
so  tight  as  to  spring  it  open.  The  corners  of  both  brasses 
where  they  fit  the  corners  of  the  strap  should  be  eased  away 
with  the  edge  of  a  half-round  file,  so  that  they  will  not  de- 
stroy the  corners  of  the  strap  (when  the  brasses  are  being 
driven  in  and  out  to  fit),  which  would  make  the  strap  appear 
to  be  a  bad  fit  on  the  rod. 

While  fitting  the  top  brass,  it  is  necessary  to  try  the  strap 
on  the  rod  end  (the  brasses  being  in  their  places)  at  inter- 
vals, so  as  not  to  take  any  more  off  the  top  brass  than  is 
necessary  to  let  the  strap  fit  the  rod  end.  As  a  guide,  when 
fitting  the  brasses  to  the  strap,  the  calipers  may  be  set  ti 


FITTING   CONNECTING  RODS. 


317 


the  width  of  the  rod  end  where  the  strap  fits,  aiid  applied 
to  the  strap  when  the  brasses  are  driven  in  to  fit.  The  gib 
and  key  must,  when  placed  together  edgeways,  be  quite 
parallel  in  their  total  breadth,  so  that  they  will  fit  properly 
against  each  other  and  against  the  keyway  in  the  rod  end 
and  the  strap.  When  setting  the  gauge  for  the  size  to  which 
the  brasses  are  to  be  planed,  place  the  strap  on  the  rod  end 
to  get  the  correct  size,  for  the  strap  is  narrower  (between 
its  jaws)  when  it  is  off  than  when  it  is  on  the  rod,  because 
of  the  spring.  In  bedding  the  back  brass  to  the  strap,  let 


Fig.  256. 


Fig.  257. 


it  bear  the  hardest,  if  anything,  upon  the  crown,  for  if  the 
bevels  of  the  brass  should  keep  the  crown  from  bedding, 
the  strap  would  spring  away  from  the  rod  end,  in  spite  of 
the  gib  (or  the  bolts,  if  there  are  any),  when  the  key  is 
driven  home,  as  illustrated  in  Fig.  256. 

If  the  back  brass  does  not  bed  down  upon  the  crown  a 

of  the  strap,  the  latter  will  spring  away  from  the  block  end 

of  the  rod  and  from  the  brasses  on  the  sides,  and  will  assume 

the  shape  denoted  by  the  dotted  lines.    Should  the  top  brass 

27 :" 


318  COMPLETE  PRACTICAL  MACHINIST. 

not  bed  properly  against  the  rod  end,  the  strap  will  spring 
as  described  in  Fig.  257. 

The  dotted  line  a  is  the  back  of  the  brass,  supposed  to 
bed  improperly  against  the  rod  end,  as  shown ;  the -p.  ~ro 
dotted  lines  B  B  denote  the  manner  in  which 
the  strap  would,  in  consequence,  spring  away  from 
the  rod  end  when  the  key  was  driven  home.  If  the 
brasses  fail  to  fit  properly  against  the  rod  end  or 
strap,  in  the  direction  of  the  breadth  of  the  strap, 
it  will  spring  out  of  line,  as  described  in  Fig.  258. 
which  is  a  sectional  view  of  a  connecting  rod  end. 
C  is  the  strap,  D  is  the  rod  end,  and  B  B  are  the 
brasses,  the  top  one  of  which,  if  it  did  not  fit  square 
against  the  rod  end  (but  on  one  side  only),  as 
represented  by  the  line  a,  would  spring  the  strap 
out  of  true  with  the  rod  end,  in  the  direction  of  the 
dotted  lines.  The  strap  is,  by  reason  of  its  shape, 
very  susceptible  to  spring ;  and  unless  the  brasses, 
or  even  the  gib  and  key,  are  quite  square  and  fit  well,  it  is 
certain  to  spring  out  of  true.  The  brasses  should  be  a  fit 
on  the  journal  when  they  are  "  brass  and  brass,"  that  is,  the 
joint  of  the  two  brasses  close  together,  so  as  to  take  the 
pressure  of  the  key,  which  thus  locks  the  strap  and  brasses 
to  the  rod  end,  and  prevents  them  from  moving,  or  working, 
as  it  is  called,  when  the  rod  is  in  action ;  especially  is  this 
necessary  in  straps  having  a  gib  and  key  to  hold  them  to 
their  places,  because,  if  the  joint  of  the  brasses  is  not  close, 
the  key  cannot  be  driven  home  tightly,  and  hence  there  is 
nothing  to  lock  the  strap  firmly  to  its  place.  If,  however, 
the  strap  is  held  to  its  place  by  bolts,  it  is  not  so  imperative 
to  keep  the  joint  of  the  brasses  close  together,  although  it  is 
far  preferable  to  do  so,  especially  in  the  case  of  fast-running 
engines,  not  only  on  account  of  the  assistance  lent  by  the 
key  to  hold  the  strap  firmly,  but  also  because  it  holds  the 
brasses  firmly,  and  the  key  cannot  bind  the  brasses  too 
tightly  to  the  journal,  even  though  the  key  be  driven  tightly 


FITTING   CONNECTING   RODS.  319 

home,  so  as  to  assist  the  set  screw  in  preventing  it  from 
slacking  back. 

The  brasses  should  be  left  a  little  too  tight  in  the  strap 
before  boring,  because  they  invariably  shrink  or  go  in  a 
little  sideways  from  being  bored,  as  do  all  brasses,  large  or 
small,  even  if  bored  before  any  other  work  has  been  done 
on  them. 

For  driving  the  brasses  in  and  out  of  the  strap  to  fit 
them,  use  a  piece  of  hard  wood  to  strike  on  so  as  not  to 
stretch  the  skin  of  the  brass  and  alter  its  form,  as  already 
explained  in  the  remarks  on  pen  ing. 

The  brasses  should  be  of  equal  thickness  from  the  face 
forming  the  joint  to  the  back  of  the  brass,  so  that  the 
joint  will  be  in  the  centre  of  the  bore  of  the  brasses.  The 
respective  faces  forming  the  joint  should  be  quite  square 
with  both  the  faces  and  sides  of  the  brass,  so  that  they  will 
not  spring  the  strap  when  they  are  keyed  up,  and  so  that, 
when  the  brasses  are  let  together  in  consequence  of  the 
bore  having  worn,  the  faces  may  be  kept  square,  and  thus 
be  known  to  fit  properly  together  without  having  to  put 
them  together  in  the  rod  and  on  the  journal  to  try  them, 
which  would  entail  a  good  deal  of  unnecessary  labor. 

To  get  the  length  of  a  connecting  rod,  place  the  piston 
in  the  centre  of  its  stroke,  and  the  distance  from  the  centre 
of  the  crosshead  pin  to  the  centre  of  the  crank  shaft  is  the 
length  of  the  rod  from  centre  to  centre  of  the  brasses. 
Another  method  is  to  place  the  piston  at  one  end  of  its 
stroke  and  the  crank  on  its  dead  centre  corresponding  ta 
the  same  end  of  the  stroke,  and  the  distance  from  the  cen- 
tre of  the  crosshead  pin  to  the  centre  of  the  crank  pin  is 
the  length  of  the  rod. 

To  ascertain  when  the  crank  of  a  horizontal  engine  is 
upon  its  exact  dead  centre,  strike  upon  the  end  face  of  the 
crank  axle  or  engine  shaft  a  circle  true  with  the  shaft,  and 
of  the  same  diameter  as  the  crank-  pin :  then  place  a  spirit 
level  so  that  one  end  rests  on  the  crank  pin  and  the  other 


320  COMPLETE  PRACTICAL  MACHINIST. 

end  is  even  with  the  outline  of  the  circle ;  and  when  the 
spirit  level  stands  true,  the  crank  will  be  upon  its  dead 
centre. 

The  length  of  a  connecting  rod  cannot  be  taken  if  the 
crank  is  placed  in  the  position  known  as  full  power, 
because  the  position  in  which  the  piston  would  then  be 
cannot  practically  be  definitely  ascertained ;  for  the  angle 
at  which  the  connecting  rod  stands  causes  the  piston  to 
have  moved  more  or  less  than  half  the  length  of  the  stroke 
when  the  crank  has  moved  from  a  dead  centre  to  full 
power,  according  to  which  end  of  the  cylinder  the  piston 
moved  from.  If  it  was  the  end  nearest  to  the  crank,  the 
piston  moved  less,  if  the  other  end,  it  moved  more,  than 
half  of  its  stroke ;  so  that  in  either  case  the  piston  stands 
nearer  the  crank  than  is  the  centre  of  the  length  of  the 
cylinder  when  the  crank  is  in  the  position  referred  to. 
This  variation  of  piston  movement  to  crank  movement  is 
greater  in  the  case  of  short  connecting  rods  than  with  long 
ones. 

To  fit  a  connecting  rod  to  an  engine,  first  rub  some 
marking  on  the  crank  pin,  and  put  the  crank  pin  end  of 
the  rod  on  its  place,  with  the  brasses  in  and  keyed  prop- 
erly up.  The  other  end  of  the  rod,  being  free,  can  be 
placed  so  as  to  touch  against  the  crosshead  pin,  when  the 
eye  will  detect  if  it  will  go  into  its  place  without  any  spring 
sideways ;  if  it  will  do  so,  the  rod  may  be  taken  off  the 
crank  pin,  and  the  brasses,  if  necessary,  fitted  to  the  pin 
sufficiently  to  allow  each  to  bear  on  the  crown.  But  if 
the  rod  end  will  not  fall  into  the  crosshead  journal  without 
being  sprung  sideways,  then  move  it  clear  of  the  cross- 
head,  placing  a  side  pressure  on  it  in  the  direction  in  which 
it  wants  to  go  to  come  fair  with  the  crosshead  journal,  and 
move  it  back  and  forth  under  such  side  pressure,  which 
process  will  cause  the  crank  pin  to  mark  where  the  con- 
necting rod  brasses  want  filing  and  scraping  to  bring  the 
rod  true.  The  rod  must  then  be  taken  off,  and  the  brasses 


FITTING    CONNECTING  RODS.  321 

eased  where  the  marking  and  the  knowledge  of  which  way 
the  rod  ought  to  go  determine,  the  rod  being  placed  on  the 
crank  pin  as  before,  and  the  whole  operation  repeated 
until  the  rod  "leads"  true  with  the  crosshead  journal. 
The  crosshead  end  of  the  rod  must  be  fitted  in  like  manner 
to  the  crosshead  journal  until  the  crank  piii  end  of  the  rod 
leads  true  to  the  crank  pin  journal.  The  rod  must  then 
be  put  on  its  place,  with  both  journals  keyed  up,  and,  if 
it  can  easily  be  accomplished,  the  engine  moved  backwards 
and  forwards,  the  brasses  being  then  taken  out  and  bedded, 
when  the  rod  will  be  fitted  complete.  A  connecting  rod 
which  has  both  straps  held  by  gibs  and  keys  gets  shorter 
from  centre  to  centre  of  the  bore  of  the  brasses  as  it  wears, 
and  that  to  half  of  the  amount  of  the  wear.  This  is,  how- 
ever, generally  rectified  by  lining  up  the  brasses — that  is, 
placing  pieces  of  metal  behind  them  (they  may  be  fastened 
to  the  brasses  if  it  is  desirable) — which  pieces  are  made 
of  the  required  thickness  to  replace  the  amount  of  the  wear 
of  the  brasses. 

A  connecting  rod  whose  crosshead  end  has  a  strap  with 
a  gib  and  key,  or,  what  is  better,  two  gibs  and  a  key,  to 
hold  it,  the  crank  pin  end  having  its  strap  held  by  bolts, 
and  the  key  between  the  bolts  and  the  brass,  would  maintain 
its  original  length,  providing  the  wear  on  the  crosshead 
brasses  was  as  great  as  is  the  wear  on  the  crank  pin 
brasses ;  but  since  that  on  the  latter  is  the  greatest,  the  rod 
wears  longer  to  half  the  amount  of  the  difference  of  the 
wear  between  the  crosshead  and  crank  pin  journals.  If 
both  the  straps  of  a  rod  are  held  by  bolts,  the  key  of  one 
end  being  between  the  brasses  and  the  main  body  of  the 
rod,  and  the  key  of  the  other  end  between  the  brasses  and 
the  crown  of  the  strap,  it  would  maintain  its  original 
length  if  the  wear  on  both  ends  was  equal ;  but  this  not 
being  so,  it  wears  longer,  as  above  stated.  When  mark- 
ing the  length  of  the  rod  (that  is,  the  circle  on  the  brasses 
to  set  them  by  for  boring),  or  when  trammeling  a  j>.d  *o  try 


322 


COMPLETE  PRACTICAL  MACHINIST. 


its  length,  stand  it  on  its  edge ;  because  if  it  rests  on  its 
broad  i'ace  the  rod  will  deflect,  and  appear  to  be  shorter 
than  it  is ;  this  is  especially  liable  to  occur  in  coupling  or 
side  rods,  which  are  generally  longer  and  slighter  in  body 
than  connecting  rods. 

The  oil  hole  of  a  strap  for  either  a  connecting  or  side 
rod  should  be  in  the  exact  centre  of  the  space  intended  to 
be  filled  by  the  brasses.  It  will  thus  be  central  with  the 
joint  of  the  brasses,  and  from  centre  to  centre  of  the  oil 
holes,  and  will,  therefore,  represent  the  proper  length  of 

Fig.  259. 


the  rod.  If  the  oil  hole  of  the  strap  has  been  drilled  to 
give  the  rod  length  as  already  explained,  and  new  brasses 
have  been  fitted  in,  the  bore  may  be  marked  out  as  in 
Fig.  259,  there  being  a  piece  of  wood  or  metal  driven  in 
the  bore,  and  the  line  E  being  carried  down  by  a  try- 
square,  and  marked  at  D  ;  lines  A  and  B  are  obtained  from 
the  inside  faces  of  the  strap  jaws,  and  from  these  the 
center  is  obtained,  wherefrom  to  mark  a  circle  to  set  the 
brasses  by  when  chucking  them  to  be  bored  . 

In  some  cases,  however,  the  brasses  do  not  abut  one 


FITTING   CONNECTING  RODS. 


323 


against  the  other,  but  are  left  open  as  in  Fig.  260,  and  in 
this  event  the  piece  of  wood  must  be  placed  across  the  bore 
as  denoted  by  D  in  Fig.  260,  the  line  B  representing  the 
center  of  the  oil  hole  or  the  length  of  the  rod. 

The  brasses  should  be  so  filed  that  lines  as  A  in  the 

Fig.  260. 


figure  marked  level  with  each  face  will  be  equidistant 
from  B,  and  to  accomplish  this  result,  each  brass  must  be 
laid  upon  a  surface  plate  and  tested  with  inside  calipers, 
as  in  Fig.  261. 

In  letting  brasses  together  to  take  up  the  wear,  we  must 

Fig.  261. 


in  brasses  that  abut  against  each  other,  or  cone  brass  and 
brass,  as  it  is  termed,  try  them  with  calipers,  applying  the 
square  both  ways  on  the  joint  faces,  for  if  the  joint  faces 
are  at  an  angle  instead  of  being  square  across,  then  driv- 
ing up  the  key  will  spring  the  brass  faces  out  of  level  one 
with  another.  Or  if  the  faces  are  out  of  square  instead 


324  COMPLETE  PRACTICAL   MACHINIST. 

of  being  square  across,  then  driving  home  the  key  will 
spring  the  strap  jaws  open  sideways. 

In  lining  up  brasses  to  set  the  key  up  in  such  a  rod  end 


Fig.  262. 


as  is  shown  in  Fig.  262,  the  liner  L  will  be  the  one  that 
determines  the  rod  length,  that  at  E  simply  serving  to 
regulate  the  key  height  and  not  affecting  the  rod  length. 

Fig.  263. 


P 


But  when  the  strap  is  bolted  to  the  rod  end,  as  in  Fig.  263, 
the  back  liner  at  L  determines  the  rod  length,  and  that 
at  E  is  the  one  that  raises  the  key. 


VISE-  WORK— DRIFTS.  325 

DRIFTS. 

Of  drifts  there  are  two  kinds,  one  being  a  smooth  round 
conical  pin,  employed  by  boiler  makers  to  make  the 
punched  holes  in  boiler  plates  come  fair,  so  that  the  rivets 
may  enter,  which  may  be  aptly  termed  a  stretching  drift, 
and  the  other  the  toothed  or"  cutting  drift.  Of  the  first  it 
is  to  be  observed  that  in  some  modern  practice  the  holes 
in  boiler  plates  are  drilled,  and  are  therefore  more 
accurately  spaced  than  it  is  practicable  to  punch  them, 
thus  greatly  reducing  the  necessity  to  drift  them;  fur- 
thermore in  the  best  practice  the  drilling  is  done  after 
the  plates  have  been  bent  into  shape,  thus  dispensing 
altogether  with  the  use  of  the  drift-pin,  which  in  the  case 
of  the  badly  matched  holes  found  in  punched  plates  greatly 
impairs  the  strength  of  the  rivetted  joint.  The  punching 
of  a  plate  considerably  weakens  its  strength  at  the  narrow- 
est section  of  metal,  namely,  between  the  hole  and  the 
edge  of  the  plate,  where  the  latter,  being  the  weakest,  gives 
way  to  the  pressure  of  the  punch.  If  one  closely  observes 
the  surface  of  a  piece  of  iron  which  is  being  punched,  he 
will  find  that  the  scale  on  the  surface  of  the  iron  round  the 
hole,  and  especially  between  the  hole  and  the  edge  of  the 
plate,  will  be  sensibly  disturbed,  showing  a  partial  disinte- 
gration of  the  grain  of  the  metal  beneath,  even  if  the  punch 
is  very  sharp ;  but  if  the  punch  is  dull,  or  the  edge  is  in 
the  least  rounded  by  wear,  the  scale  will  fly  off  the  surface 
of  the  metal  in  small  particles,  evidencing  a  considerable 
disturbance  of  the  metal  beneath  and  an  equivalent  weak- 
ening of  the  substance  between  the  edge  of  the  hole  and 
the  edge  of  the  plate.  If,  then,  after  punching,  the  holes 
do  not  come  fair,  and  the  plain  drift  is  employed  to  still 
further  stretch  the  metal,  not  only  is  the  weakening  pro- 
cess greatly  augmented,  but  the  holes  are  stretched  oval, 
so  that  the  rivets  do  not  completely  fill  them,  however  well 
the  riveting  may  be  performed.  The  use  of  the  plain  drift 
is  therefore  totally  incompatible  with  first-class  work- 
28 


326 


COMPLETE  PRACTICAL  MACHINIST. 


manship ;  hence  a  description  of  this  tool  will  be  altogether 
omitted. 

Of  cutting  drift?,  there  are  two  kinds,  the  first  being  that 
shown  in  Fig.  264.  A  is  the  cutting  edge,  the  width  and 
thickness  at  C  and  B  being  reduced  so  that  the  sides  of  the 
drift  may  clear  the  sides  of  the  hole.  The  drift  is  filed 
at  A  A,  to  suit  the  required  hole,  and  tempered  to  a  brown 
bordering  upon  a  purple.  The  hole  or  key  way  is  then  cut 


Fig.  264. 


Fig.  265. 


out  roughly,  to  nearly  the  required  size,  and  the  drift  is 
then  driven  through  with  a  hand  hammer,  cutting  a  clean 
and  true  hole.  Care  must,  however,  be  taken  to  have  the 
work  rest  evenly  upon  a  solid  block  of  iron  or  (for  delicate 
work)  lead,  and  to  strike  the  punch  fair  and  evenly,  other* 
wise  a  foul  blow  may  break  the  drift  across  the  section  at 
C.  This  class  of  drift  is  adapted  to  small  and  short  holes 


VISE-  WORK— DRIFTS.  327 

only,  such  as  cotter  ways  in  the  ends  of  keys  or  oolts,  for 
which  purposes  it  is  a  very  serviceable  and  strong  tool.  It 
must  be  freely  supplied  with  oil  when  used  upon  wrought- 
iron  or  steel. 

For  deeper  holes,  or  those  requiring  to  be  very  straight, 
true,  and  smooth,  the  drift  represented  by  Fig.  265  is  used. 
The  breadth  and  thickness  of  the  section  at  A  is  made  to 
suit  the  shape  of  the  keyvvay  or  slot  required.  The  whole 
body  of  the  drift  is  first  filed  up  parallel  and  smooth,  to 
the  required  size  and  shape;  the  serrations  forming  the 
teeth  are  then  filed  in  on  all  lour  sides,  the  object  of  cutting 
them  diagonally  being  to  preserve  the  strength  of  the  cross 
section  at  A  A.  The  teeth  may  be  made  finer,  that  is, 
closer  together,  for  very  fine  work,  their  depth,  however, 
being  preserved  so  as  to  give  room  to  the  cuttings.  To 
attain  this  object  in  dr  if  to  of  large  size,  the  teeth  should  be 
made  as  shown  in  Fig.  265,  which  will  give  room  for  the 
cuttings,  and  still  leave  the  teeth  sufficiently  strong  that 
they  do  not  break.  The  head  B  of  the  drift  is  tapered 
off,  so  that,  when  it  swells  from  being  struck  by  the  ham- 
mer, it  will  still  pass  through  the  hole,  since  this  drift  is 
intended  to  pass  clear  through  the  work. 

The  method  of  using  this  tool  is  as  follows :  The  holo 
should  be  roughed  out  to  very  nearly  the  required  size, 
leaving  but  a  very  little  to  be  taken  out  by  the  drift, 
whose  duty  is,  not  to  remove  a  mass  of  metal,  but  to  cut  a 
true  and  straight  hole.  To  assist  in  roughing  out  the  hole 
true,  the  drift  may  be  driven  lightly  in  once  or  twice,  and 
then  withdrawn,  which  will  serve  to  mark  where  metal  re- 
quires to  be  removed.  When  the  hole  is  sufficiently  near 
the  size  to  admit  of  being  drifted,  the  work  should  be 
bedded  evenly  upon  a  block  of  iron  or  lead,  and  oil  sup- 
plied to  both  the  hole  and  the  drift ;  the  latter  is  then 
driven  in,  care  being  exercised  that  the  drift  is  kept  up- 
right in  the  hole.  If,  however,  the  hole  is  a  long  one,  and 
the  cuttings  clog  in  the  teeth,  or  the  cut  becomes  too  great, 


328  COMPLETE  PRACTICAL  MACHINIST. 

which  may  be  detected  by  the  drift  making  but  little 
progress,  or  by  the  blow  on  the  drift  sounding  solid,  the 
drift  may  be  driven  out  again,  the  cuttings  removed,  the 
surplus  metal  (if  any  there  be  in  the  hole)  cut  away,  the 
hole  and  drift  again  freely  oiled,  and  the  drift  inserted  and 
driven  in  as  before,  the  operation  being  continued  until  the 
drift  passes  entirely  through  the  hole;  for  the  drift- will  be 
sure  to  break  if  too  much  duty  is  placed  upon  it,  After 
the  drift  has  passed  once  through  the  hole,  it  should  be 
turned  a  quarter  revolution,  and  again  driven  through,  and 
then  twice  more,  so  that  each  side  of  the  drift  will  have 
contacted  with  each  side  of  the  hole  (supposing  it  to  be  a 
square  one),  which  is  done  to  correct  any  variation  in  the 
size  of  the  drift,  and  thus  to  cut  the  hole  true. 

The  great  desideratum  in  using  these  drifts  is  to  drive 
them  true,  and  to  strike  fair  blows,  otherwise  they  will 
break.  While  the  drift  is  first  used,  it  should  be  examined 
for  straightness  at  almost  every  blow;  and  if  it  requires 
drawing  to  one  side,  it  should  be  done  by  altering  the  direc- 
tion in  which  the  hammer  travels,  and  not  by  tilting  the 
hammer  face  (see  Fig.  266). 

Suppose  A  to  be  a  piece  of  work  and  B  and  C  to  be 
drifts  which  have  entered  the  keyways  out  of  plumb,  as 
shown  by  the  dotted  lines  D  and  E.  If,  to  right  the 
drift  C,  it  was  struck  by  the  hammer  F,  in  the  position 
shown  and  travelling  in  the  direction  denoted  by  G,  the 
drift  C  would  be  almost  sure  to  break  ;  but  if  the  drift  B 
was  struck  by  the  hammer  H,  as  shown,  and  travelling  in 
the  direction  denoted  by  I,  it  would  draw  the  drift  B  up- 
right without  breaking  it;  or  in  other  words,  the  hammer 
face  should  always  strike  the  head  of  the  drift  level  and 
true  with  it,  the  drawing  of  the  drift,  if  any  is  required, 
being  done  by  the  direction  in  which  the  hammer  travels. 
When  it  is  desired  to  cut  a  very  smooth  hole,  two  or  more 
drifts  should  be  used,  each  successive  one  being  a  trifle 
larger  in  diameter  than  its  predecessor.  Drifts  slight  in 


REVERSE  KEYS. 


329 


cross  section,  or  slight  in  proportion  to  their  lengths, 
should  be  tempered  evenly  all  over  to  a  purple  blue,  those 
of  stout  proportions  being  made  of  a  deep  brown  bordering 
upon  a  bright  purple.  For  cutting  out  long  narrow  holes, 
the  drift  has  no  equal,  and  for  very  true  holes  no  substitute. 


/; 


It  must,  however,  be  very  carefully  used,  in  consequence 
of  its  liability  to  break  from  a  jarring  blow. 

REVERSE    KEYS. 

Crossheads,  pistons,  and  other  pieces  of  work  which  are 
keyed  to  their  places  upon  taper  rod  ends,  and  are  therefore 

28 


330 


COMPLETE  PRACTICAL  MACHINIST. 


apt  to  become  locked  very  fast,  are  easily  removed  by 
nieaDS  of  reverse  keys,  which  should  always  be  employed 
for  that  purpose,  because  striking  such  work  with  a  ham- 
mer, even  supposing  the  work  to  be  well  supported  under- 
neath and  copper  interposed  between  the  hammer  and  the 
work,  is  liable  to  bend  and  otherwise  damage  it  with  every 
heavy  blow. 

Reverse  keys  are  simple  pieces  of  steel,  so  shaped  as  to 
reverse  the  draft  of  a  key  way,  and  are  made  male  and 
female,  as  shown  in  Fig.  267,  A  representing  the  male,  and 
B  the  female.  The  manner  of  using  them  is  to  insert 
them  into  the  keyway,  as  shown  m  Fig.  268,  in  which  A 


Fig.  267. 


Fig.  268. 


B 


T 


A 


I 


represents  a  taper  rod  end,  B  the  socket  into  which  A  is 
fitted  or  keyed,  C  the  male  and  D  the  female  reverse  key, 
and  E  an  ordinary  key.  It  will  be  found,  on  examination, 
that  the  insertion  of  C  and  D  have  exactly  reversed  the 
position  of  the  draft  of  the  keyway,  so  that  the  pressure  due 
to  driving  in  the  key  will  be  brought  to  bear  upon  the  rod 
on  the  side  on  which  the  pressure  was  previously  on  the 
socket,  and  on  the  socket  on  the  side  on  which  the  pressure 
was  on  the  rod ;  so  that  driving  in  the  key  will  key  the 
socket  out  of  instead  of  into  its  place. 

The  keyway  in  Fig.  268  is  shown  to  have  draft ;  that  is, 
the  proper  key,  when  driven  in,  will  bear  one  edge  upon 


SETTING  LINE-SHAFTING  IN  LINE. 


331 


the  edge  of  the  keyway  in  the  rod  only,  and  not  on  the 
edge  of  the  keyway  in  the  socket  at  the  small  end  of  the 
cone ;  while  at  the  large  end,  the  natural  key  would  bear 
against  the  edge  of  the  keyway  in  the  socket  only.  If 
however,  this  condition  does  not  exist,  and  the  edges  of  the 
key  bear  equally  upon  the  cone  and  the  socket  (on  both 
edges  and  all  the  way  through),  the  keyway  being  a  solid 
one,  that  is  to  say,  having  no  draft,  the  reverse  keys  may 
be  employed,  providing  that  C  is  placed  so  as  to  bear  upon 
the  edge  of  the  keyway  on  the  large  end  of  the  cone  only, 
and  that  D  is  placed  to  bear  on  the  edge  of  the  keyway 
at  the  small  end  of  the  cone  on  the  socket  only,  thus  pro- 
ducing a  back  draft,  or  clearance,  as  it  may  better  be 
termed.  The  key  E  should  be  made  long,  and  both 
it  and  the  reverse  keys  should  be  made  of  steel  and  left 
soft. 

SETTING    LINE-SHAFTING   IN    LINE. 

To  set  a  length  or  line  of  shafting  in  line,  first  prepare 
a  number  of  wooden  frames  or  targets,  such  as  in  Fig. 


1 
<. 

^ 

7 

r.  269. 

I1.!1 
Hfi 

5 

A 

1 

1  } 

'\ 
'l 

/ 

*'/ 

r^^^^i^^ 

9     /  ' 

; 

<A 

'/j. 

« 

\ 

j 

I 

0 

o 
o 

>~^~'^^t== 

269,  the  outer  edge  A  being  planed  straight,  and  there 
being  marked  a  line  B  parallel  to  A.  Upon  this  frame 
hangs  the  plumb-bob,  shown  at  B,  so  that  when  the 
plumb  line  is  fair  with  the  marked  line  the  edge  A  will 
stand  vertical.  Having  erected  these  targets  at  each  end 


332 


COMPLETE  PRACTICAL  MACHINIST. 


of  each  length  of  shafting,  we  stretch   a  fine  string  or 
silk   line   beside   the  line  of  shafting,  as   in  Fig.  270, 

fig.  270. 


placing  it  about  6  inches  below  and  on  one  side  of  the 
shafting,  and  adjusting  it  at  first  as  nearly  parallel  to  the 

Fig.  271. 


shaft  as  can  be  judged  by  the  eye.     If  the  line  of  shafting 
is  of  equal  diameter  at  each  end,  we  may  set  the  stretched 


SETTING  LINE-SHAFTING  IN  LINE.  333 

liiie  equidistant  from  it  at  each  end  ;  while  if  one  end  is 
of  larger  diameter  than  the  other,  we  set  the  line  parallel 
to  the  shafting  axis,  and  horizontally  true  as  near  as  it 
can  be  set  by  a  spirit  level.  The  targets  must  now  be  ad- 
justed as  follows:  the  planed  edge  is  brought  up  so  as  to  just 
touch  the  stretched  line,  while  its  edge  A  is  vertical,  which 
will  be  known  from  the  plumb  line  covering  the  line 
marked  beneath  it  and  parallel  to  edge  A.  Each  target 
is  set  in  this  way  and  nailed  fast  or  secured  in  any  con- 

Fig.  272. 


veuient  manner,  as  in  Fig.  271.  We  have  now  in  the 
planed  edges  A  of  the  target  a  substitute  for  the  stretched 
line,  and  forming  a  guide  for  the  horizontal  adjustment  of 
the  line  of  shafting.  For  the  vertical  adjustment  we  take 
a  wooden  straight-edge  long  enough  to  reach  from  one 
'target  to  the  next  one,  and  beginning  at  one  end  of  the 
shafting  we  place  the  flat  side  of  the  straight-edge  against 
the  planed  edges  of  two  of  the  targets  at  a  distance  of  say 
15  inches  below  the  top  of  the  shafting,  and  after  levelling 


S34 


COMPLETE  PRACTICAL  MACHINIST. 


i. 


the  straight-edge  with  a  spirit  level,  we  mark  even  with 
the  edge  of  the  straight-edge  a  line  on  the  planed  edge  A 
of  both  of  the  targets.  We  then  move  the  straight-edge  so  as 
to  embrace  the  next  target,  set  one  end  even  with  the  line 
already  marked  on  the  second  target,  and  set  it 
Fig,  273.  true  by  a  spirit  level  and  mark  a  line  on  the 
edge  of  the  third  target,  the  straight-edge  being 
shown  in  Fig.  272,  in  position  to  mark  the  line 
on  the  third  target.     By  continuing  this  process 
we  shall  have  marked  a  line  across  the  edges 
of  all  the  targets,  and  from  this  line  the  shafting 
may  be  set  as  follows :  A  square  having  its  edges, 
A  and  B,  at  a  right  angle  to  one  another  has  a 
line  C   marked  upon    it  at  a   distance  below 
the  edge  A  of  15  inches  (this  being  the  distance  we  set 
the  stretched  line  below  the  shafting  axis),  from  line  C 
on  the  square  as  a  centre  we  mark  below  it  a  line  F, 
in    Fig.  273,    distant   from   C   to    an    amount   equal    to 
half  the  diameter  of  the  line  shaft,  and 
if  the  shafting  is  parallel  in  diameter  we 
may  rub  out  line  C  and  leave  line  F  only 
on  the  square.     All  that  remains  to  do  is 
to   apply    the   square    to    the   edge   of 
each     target,    and     to    the    shaft,    and 
when   the  line  on  the  square  coincides 
with  the  line  on  the  target,  the  shafting 
is  set  true  and  level.     For  the  horizontal 
adjustment  all  we  have  to  do  is  to  place 
a  straight-edge  on  the  edge  of  the  target, 
as  in  Fig.  274,  and  adjust  the  shaft  by  a 
distance-piece  D. 
There  are  several   points,  however,  during  the  latter 
part  of  the  process  at  which  consideration  is  required. 

Thus,  after  the  horizontal  line,  marked  on  the  targets 
by  the  straight-edge  and  used  for  the  vertical  adjustment, 
has  been  struck  on  all  the  targets,  the  distance  from  the 


Fig.  274. 


SETTING  LINESHAFT1NG  IN  LIKE.  335 

centre  of  the  shafting  to  that  line  should  be  measured  at 
each  end  of  the  shafting,  and  if  it  is  found  to  be  equal,  we, 
may  proceed  with  the  adjustment. 

But  if,  on  the  other  hand,  it  is  not  found  to  be  equal 
we  must  determine  whether  it  will  be  well  to  lift  one  end 
of  the  shaft  and  lower  the  other,  or  make  the  whole  ad- 
justment at  one  end  by  lifting  or  lowering  it  as  the  case 
may  be. 

In  coming  to  this  determination  we  must  bear  in  mind 
what  effect  it  will  have  on  the  various  belts,  in  making 
them  too  long  or  too  short,  and  when  a  decision  is  reached, 
we  must  mark  the  line  C,  in  Fig.  273,  on  the  gauge,  accord- 
ingly, and  not  at  the  distance  represented  in  our  example 
by  the  15  inches. 

The  method  of  adjustment  thus  pursued  possesses  the 
advantage  that  it  shows  how  much  the  whole  line  of 
shafting  is  out  of  true  before  any  adjustment  is  made,  and 
that  without  entailing  any  great  trouble  in  ascertaining 
it;  so  that  in  making  the  adjustment  the  operator  acts 
intelligently  and  does  not  commence  at  6"ne  end  utterly 
ignorant  of  where  the  adjustment  is  going  to  lead  him  to 
when  he  arrives  at  the  other. 

Then,  again,  it  is  a  very  correct  method,  nor  does  it 
make  any  difference  if  the  shafting  has  sections  of  differ- 
ent diameters  or  not,  for  in  that  case  we  have  but  to 
measure  the  diameter  of  the  shafting,  and  mark  the 
adjusting  line,  represented  in  our  example  by  C,  in  Fig. 
273,  accordingly,  and  when  the  adjustment  is  completed, 
the  centre  line  of  the  whole  length  of  the  line  of  shafting 
will  be  true  and  level. 

This  is  not  necessarily  the  case  if  the  diameter  of  the 
shafting  varies  and  a  spirit  level  is  used  directly  upon 
the  shafting  itself.  In  further  explanation,  however,  it 
may  be  well  to  illustrate  the  method  of  applying  the 
gauge  shown  in  Fig.  273,  and  the  straight-edge  C  and 
gauge  D,  shown  in  Fig.  274,  in  cases  where  there  are  in 


336  COMPLETE  PRACTICAL  MACHINIST. 

the  same  line  sections  of  shafting  of  different  diame- 
ters. 

Suppose  then  that  the  line  of  shafting  in  our  exam- 
ple has  a  mid-section  of  2-J  inches  diameter,  and  is  2 
inches  at  one,  and  2£  inches  in  diameter  at  the  other 
end. 

All  we  have  to  do  is  to  mark  on  the  gauge,  shown  in 
Fig.  273,  two  extra  lines  denoted  in  the  Fig.  by  D  and  F. 

If  the  line  C  was  at  the  proper  distance  from  A  for 
the  section  of  2|  inches  in  diameter,  then  the  line  D  will 
be  at  the  proper  distance  for  the  section  of  2  inches,  and 
Eat  the  proper  distance  for  the  section  of  2^  inches  diameter, 
the  distance  between  C  and  D,  and  also  between  C  and  E, 
being  \  inch ;  in  other  words,  half  the  amount  of.  the 
difference  in  diameters. 

In  like  manner,  for  the  horizontal  adjustment,  the  gauge 
piece  shown  at  D,  in  Fig.  274,  would  require,  when  measur- 
ing the  2^  inches  section,  to  be  \  inch  shorter  than  for 
the  2^  inches  section,  while  for  the  2£  inches  section  would 
require  to  be  |  inch  shorter  than  that  used  for  the  2£ 
inches  section,  the  difference  again  being  J  the  amount 
of  the  variation  in  the  respective  diameters.  Thus  the 
whole  process  is  simple,  easy  of  accomplishment,  and 
very  accurate.  If  the  line  of  shafting  is  suspended  from 
the  posts  of  a  ceiling  instead  of  from  uprights,  the  method 
of  procedure  is  the  same,  the  forms  of  the  targets  being 
varied  to  suit  the  conditions.  The  process  only  requires 
that  the  faced  edges  of  the  targets  shall  all  stand  plumb 
and  true  with  the  stretched  line.  It  will  be  noted  that 
the  plumb  lines  (shown  on  the  target  in  Fig.  269  at  B)  are 
provided  simply  as  guides,  whereby  to  set  the  targets,  and 
are  put  at  about  |  inch  inside  of  the  planed  edge  so  as  to 
be  out  of  the  way  of  the  stretched  line.  It  is  of  no  con- 
sequence how  long  the  stretched  line  is,  since  its  sag  does 
not  in  any  manner  disturb  the  correct  adjustment;  but  in 
cases  where  it  is  a  very  long  one  it  may  be  necessary  to 


SETTING  LINESHAFTING  IN  LINE.  337 

place  pins  that  will  prevent  it  from  swaying  by  reason 
of  air  currents  or  from  jarring. 

The  same  system  may  be  employed  for  setting  the  shaft- 
ing hangers,  the  bores  of  the  boxes  being  used  instead 
of  the  shafting  itself. 
29 


CHAPTER    XVI. 

MILLING-MACHINES   AND   MILLING-TOOLS. 

THE  position  occupied  by  the  milling-machine  in  modern 
practical  mechanics  is  almost  as  important  as  that  occupied 
by  the  lathe  or  planing-machine.  In  getting  out  work  by 
the  aid  of  either  of  the  latter,  the  size  and  uniformity  of 
the  work  depend  upon  the  accuracy  in  measurement,  and 
hence  upon  the  skill  of  the  operating  artisan,  hence  a 
skilled  and  expert  workman  is  necessary  to  the  use  of  each 
lathe  or  planer.  In  the  case,  however,  of  a  milling- 

Flg.  275. 


machine,  the  skilled  mechanic  has  but  to  properly  set  the 
machine  and  the  chucks  necessary  to  hold  the  work,  and  a 
less  skilful  operator  may  be  assigned  to  continue  the  opera- 
tion of  getting  out  any  number  of  similar  pieces  of  work, 
with  the  assurance  that  uniformity  of  size  and  form  and 
equality  of  finish  may  be,  with  ordinary  care,  assured. 
Then,  again,  intricate  forms  and  shapes  of  work  may  be 
exactly  and  easily  duplicated  by  the  employment  of 
338 


MILLING  MACHINES  AND  TOOLS, 


339 


milling-tools,  which  would  be  impracticable  were  the  same 
work  operated  upon  by  a  planing-machine ;  especially  is 


this  the  case  in  work  of  complicated  form.  Suppose,  for 
instance,  it  were  required  to  cut  out  a  corrugated  surface, 
such  as  shown  in  Fig.  275,  it  would  be  a  difficult  matter  to 
produce,  with  a  planing-machine,  one  such  a  piece  of  work 


340 


COMPLETE  PRACTICAL  MACHINIST. 


quite  true  and  with  a  smooth  and  polished  surface,  because 
the  tool  would  be  liable  to  spring  from  the  broadness  of 
cutting  surface,  which  would,  in  the  case  of  wrought-iron 
and  steel,  cause  the  tool  to  spring  into  the  softer  and  away 
from  the  harder  parts  of  the  metal ;  and  in  the  case  of  any 
metal  it  would  be  quite  difficult  to  feed  the  tool  so  as  to 
insure  exactitude  and  avoid  tool-marks  at  the  junction  of 
the  cuts  taken  by  the  round-nosed  and  curved  tools; 
whereas,  with  a  milling-tool,  properly  made  (and  it  is  no 
difficult  matter  to  make  such  a  tool),  the  operation  is  so 
simple  that  it  may  be  per- 
formed with  comparatively  Fig.  278. 
unskilled  labor. 

One  of  the  main  advan- 
tages of  milling-tools  is  that 
the  work  will,  in  nearly  all 
cases,  be  true,  even,  and 
smooth,  even  though  the 
tool  itself  be  a  little  out  of 
true. 

Suppose,  for  example,  we 
require  to  mill  the  side 
faces  of  a  rod,  and  we  em- 
ploy for  the  purpose  the 
milling-bar  and  cutters 
shown  in  Fig.  277,  in  which  A  represents  the  spindle  of 
a  milling-machine,  and  B  B  are  milling-cutters  with  the 
distance  washer  C  interposed  between  them  to  regulate 
their  distance  apart;  D  representing  a  piece  of  work  being 
fed  between  the  revolving  cutters  B  B.  Now,  it  is  evident 
that  even  were  the  cutters  out  of  true,  the  pieces  of  work 
would  all  be  cut  to  one  size,  because  the  projecting  teeth 
of  the  cutters  will  come  into  contact  with  and  operate  upon 
each  part  of  the  surface  of  the  work  being  operated  upon, 
the  only  difference  being  that  the  work  will  be  cut  nar- 
rower with  the  same  thickness  or  length  of  washer  than  it 
would  be  were  the  washers  true. 


MILLING  MACHINES  AND   TOOLS.  341 

In  Fig.  276,  E  represents  a  view  of  the  face  of  a  milling- 
cutter,  and  F  a  sectional  view  of  the  same,  while  G  repre- 
sents a  piece  of  work  passing  under  the  cutter  and  not 
between  the  cutters,  as  shown  in  the  case  of  the  work  B. 
The  arrow  H  denotes  the  direction  in  which  the  cutter  E 
would  require  to  revolve,  and  the  arrow  I  the  direction  in 
which,  in  that  case,  the  work  would  require  to  travel  ; 
from  which  it  will  be  perceived  that  the  lateral  strain 
placed  upon  the  work  by  the  cut  is  in  a  direction  to  force 
the  work  back  from  the  cutter,  and  this  must  always,  in 
the  use  of  milling-tools,  be  the  case,  and  is  a  very  import' 
ant  consideration  for  the  following  reasons : 

From  the  breadth  of  cut  taken  by  a  milling-tool,  and 
from  the  acute  angle  at  which  the  teeth  of  the  cutter  strike 
the  cut  when  the  work  passes  below  the  circumference  of 
the  cutter,  the  strain  due  to  the  cut  is  immense ;  and  were 
this  strain  in  a  direction  to  drag  or  draw  the  work  below 
or  towards  the  cutter,  the  latter  would,  from  the  spring  of 
the  spindle,  rip  into  the  work  and  tear  its  own  teeth  off. 
Thus,  in  Fig.  278,  suppose  A  to  be  a  milling-cutter  revolv- 
ing in  the  direction  of  the  arrow  B,  and  C  to  be  a  piece  of 
work  travelling  in  the  direction  of  D,  it  will  be  readily 
perceived  that  there  will  be  an  enormous  strain  in  a 
direction  to  force  the  work  from  its  chuck  or  clamps  and 
drag  it  under  the  cutter. 

The  work  being  held  sufficiently  firm,  cannot,  it  is  true, 
move  in  that  direction  faster  than  the  rate  of  feed  will 
permit ;  but  the  teeth  grip  the  work,  the  cutter  springs 
forward  and  attempts  to  ride  like  a  spiked  wheel  over  the 
work,  and  the  cutter-teeth  break  from  the  undue  pressure ; 
and  therefore  it  is  that  in  milling  work  of  every  kind 
whatsoever,  the  direction  in  which  the  work  is  fed  should 
be  such  as  to  tend  to  force  the  work  away  from  the  cut ;  or, 
in  other  words,  the  cutters  should  cut  under  the  cut,  not 
only  because  of  the  above  imperative  reasons,  but  for  the 
tbl lowing  additional  ones : 
291- 


842 


COMPLETE  PRACTICAL  MACHINIST. 


The  skin  of  iron  or  brass  castings  and  of  iron  or  steel 
forgings  is  considerably  harder  than  is  the  interior  of  the 
metal,  in  addition  to  which  there  is  frequently  scale  in  the 
one  case  and  sand  in  the  other  to  contend  with,  so  that  if 
the  cutting  edge  of  a  tool  comes  into  contact  with  the 
outer  skin  of  the  work,  the  keenness,  and  hence  the  cutting 
value  of  the  tool  or  cutter,  becomes  rapidly  impaired ; 
and  milling-cutters  being  expensive  tools  to  make,  it  is 
desirable  that  their  cutting  edges  and  qualifications  be 
preserved  as  long  as  possible.  Suppose,  therefore,  that  in 
Fig.  270,  from  A  to  B  represents  the  depth  of  cut  on  two 

Fig.  279. 


J) 


pieces  of  work,  one  travelling  beneath  the  cutter  in  the 
direction  of  the  arrow  C,  and  the  other  in  the  direction  of  the 
arrow  I),  and  that  the  upper  surfaces  B,  in  each  case,  have 
a  hard  surface-skin  upon  them  :  it  becomes  apparent  then 
that  in  the  case  of  the  piece  represented  at  1,  the  cutter- 


MILLING   MACHINES  AND   TOOLS.  343 

teeth  will,  after  the  cut  has  once  started,  meet  the  soft 
metal  and  cut  under  the  skin  till  the  cut  has  ended,  so 
that,  save  at  the  very  commencement  of  the  cut,  the  cutter- 
teeth  would  never  meet  or  come  into  contact  with  the  hard 
surface-skin  ;  while  in  the  case  of  the  piece  of  work  2  the 
teeth  would  in  every  instance  strike  the  hard  skin  first. 
If  the  piece  of  work  E  were  held  in  the  position  shown,  it 
would  strike  the  scale,  whichever  way  the  cutters  ran  or 
the  work  was  fed ;  and  the  same  remark  applies  to  the 
piece  of  work  F.  There  is  this  difference,  however,  between 
the  two  latter  positions :  with  the  cutter  revolving  in  the 
direction  shown,  the  strain  of  the  cut  would  be  in  a  direc- 
lion  to  lift  E  from  the  machine-table,  rendering  it  very 
liable  to  spring  and  difficult  to  cut ;  while  the  strain  on  F 
would  tend  to  force  it  down  upon  the  table,  which  would 
be  far  preferable. 

When  the  side  faces  of  the  cutters  operate,  they  must  be 
made  right  and  left — that  is  to  say,  the  teeth  of  one  cutter 
must  slope  in  the  opposite  direction  to  those  on  the  other 
cutter,  so  that  when  the  two  are  placed  opposite  to  one 
another,  as  shown  in  Fig.  277,  the  teeth  of  both  will  stand 
in  a  direction  to  accommodate  the  direction  in  which  the 
cutters  revolve.  To  cut  side  faces  of  any  required  width, 
we  have  only  to  vary  the  width  apart  of  the  cutters  by  the 
washer  C,  in  Fig.  277;  while,  to  cut  curves  and  shoulders, 
the  periphery  only  of  the  cutters  can  be  used.  Thus,  sup- 
pose it  were  required  to  cut  out  the  form  shown  in  Fig. 
280,  the  outline  of  the  cutter  would  require  to  be  as  shown 
in  Fig.  281,  but  it  would  be  a  tedious  and  difficult  matter 
to  get  up  a  solid  cutter  of  such  a  fhape  on  account  of  the 
difficulty  of  cutting  the  teeth;  hence,  all  such  compound 
forms  are  produced  by  making  separate  cutters,  each  of 
its  requisite  form,  size  and  width,  and  then  placing  them 
together  to  make  up  the  whole.  Thus  the  figures  from  1 
to  8  each  represent  a  separate  cutter.  It  is  obvious  then 
that  there  is  scarcely  a  limit  to  the  forms  cnpible  of  being 


344 


COMPLETE  PRACTICAL  MACHINIST. 


.Ffy.281. 


smoothly  cut  and  uniformly  reproduced  by  such  cutters. 
The  Morse  Twist  Drill  Company  cut  the  threads  upon 
their  taps,  and  give  the  sides  of  threads  a  slight  amount 
of  clearance  back  from  the  cutting  edges  by  the  use  of 
mil  ling- tools,  producing  a  tap  equal  in  every  respect  to 
those  producible  in  the 

lathe,   and    being    re-  pig  280. 

markable  for  uniform- 
ity of  size  and  finish. 

Milling-cutters  of 
small  size  are  made 
of  solid  cast-steel ;  for 
larger  sizes,  the  body  is 
made  of  wrought-iron, 
while  the  faces  whereon 
the  cutting-teeth  are  to 
be  formed  have  steel 
welded  on  them. 

After  the  cutters  are 
bored  and  turned  to 
the  requisite  size  and 
shape,  the  spaces  neces- 
sary to  the  formation 
of  the  teeth  may  be  cut 
by  a  milling-cutter  ; 
and  here  it  may  be 
well  to  note  that  it  is 
advisable  to  keep  the 
teeth  sufficiently  wide 
apart  to  give  plenty  of 
room  for  the  cuttings 

to  escape;  even  in  cutters  for  gear-wheels,  coarse  teeth— 
that  is,  those  wide  apart — will  cut  quicker  and  smoother 
than  fine  ones,  and  have  the  advantage  that  they  entail 
much  less  labor  in  both  the  manufacture  when  new  and 
resharpening  when  dull.  After  the  spaces  are  cut  out  and 


MILLING  MACHINES  AND  TOOLS.  345 

the  teeth  formed,  the  cutter  must  be  carefully  hardened 
and  tempered  to  a  straw  color. 

Very  long  toothed  cutters,  such  as  reamers,  are  apt  to 
warp  in  the  hardening,  getting  out  of  round  as  well  as  out 
of  straight.  They  may  of  course  be  made  true  again,  by 
the  ordinary  grinding  process,  or  the  following  plan  may 
be  adopted  to  straighten  them  previous  to  sharpening  them 
in  the  usual  manner: 

The  reamer,  after  being  hardened,  should  be  revolved 
rapidly  in  the  lathe  in  one  direction,  while  an  emery- 
wheel  revolves  at  a  high  speed  in  the  opposite  direction,  as 
shown  in  Fig.  282,  A  representing  the  reamer  and  B  the 

emery-wheel ;  the  emery- 
Fi(j.  282.  wheel  should    be   fed   to 

the  reamer  just  sufficient 
to  true  the  cutting  edges. 
For  ordinary  cutters 
clearance  and  sharpening 
may  be  given  to  the  teeth 
as  follows  :  Beneath  a  re- 
volving emery-wheel,  and 
quite  parallel  and  true 

with  the  spindle  on  which  the  emery-wheel  revolves,  there 
is  provided  a  stationary  adjustable  mandril  of  such  a  size 
as  to  neatly  fit  the  centre  hole  in  the  cutter  to  be  operated 
upon  ;  which  mandril  is  of  a  sufficient  length  to  permit 
the  cutter  to  slide  along  it  and  stand  wholly  on  either  side 
of  the  emery-wheel.  The  height  of  the  mandril  is  adjusted 
so  that  the  emery-wheel  will,  when  brought  into  contact 
with  the  cutter  Awhile  the  latter  is  upon  the  mandril),  take 
off  just  sufficient  to  sharpen  and  give  clearance  to  the 
teeth.  Some  guide  is  necessary  to  insure  that  the  teeth  of 
the  cutter  shall  pass  under  the  emery-wheel  in  an  exactly 
uniform  position,  which  is  accomplished  by  providing  an 
adjustable  stationary  guide  or  gauge,  against  which  the 
radial  or  front  face  of  the  tooth  is  held  while  it  is  being 


346  COMPLETE  PRACTICAL  MACHINIST. 

ground.  The  operation  is  thus  to  place  the  cutter  on  the 
mandril  and  adjust  the  latter  to  the  requisite  height,  tc 
then  adjust  the  guide  so  that  when  the  cutter  is  moved 
forward  it  will  first  come  into  contact  with  the  guide, 
against  which  the  cutter  is  held  by  the  hand,  while  it  is  at 
the  same  time  passed  under  the  emery-wheel.  It  is  obvi- 
ous that  by  this  means  either  circumferential  or  side  face 
teeth  may  be  sharpened  and  maintained  true  if  the  bear- 
ing of  the  cutter  upon  the  mandril  is  sufficiently  long 
and  of  sufficiently  accurate  fit  to  keep  the  cutter  steady. 
There  are  other  devices  for  taper  cutters  in  which  the  latter 
are  stationary  and  the  emery-wheel  traverses  along  the 
teeth,  which  plan  is  for  taper  cutters  preferable  to  that 
first  described ;  the  principles  involved  are,  however,  the 
same  in  both  cases. 

It  must  be  remembered  that,  in  using  the  emery-wheel 
for  this  purpose,  it  must  run  under  its  cut  for  the  reasons 
already  explained  by  Fig.  278  and  its  accompanying  ex- 
planation. 

It  is  obvious  that  in  the  case  of  long  cutters  having  cir- 
cumferential teeth,  the  excessive  strain  due  to  each  tooth 
striking  the  cut  will  cause  the  mandril  carrying  the  work 
to  spring  away  from  the  cut,  the  effect  being  that  the  fin- 
ished surface  of  the  work  will  be  slightly  waved.  To 
remedy  this  defect,  the  teeth  of  the  cutter  should  be  made 
to  run  slightly  spiralled,  and  not  straight  across  the  length 
of  the  cutter,  so  that  the  cutting  edges  will  be  taking  and 
leaving  the  work  continuously,  and  hence  the  spring  above 
referred  to  will  be  at  all  times  equal.  The  same  object  is 
obtained  in  compound  cutters,  such  as  shown  in  Fig.  281, 
by  cutting  the  key  or  feather-ways  in  the  cutters,  so  that 
their  teeth  will  not  stand  in  a  line  one  with  the  other. 


CHAPTER    XVII. 

GRINDSTONE   AND   TOOL   GRINDING. 

GRINDSTONES  are  employed  for  three  purposes:  to 
smooth  surfaces,  to  reduce  metal  to  a  given  thickness,  ana 
to  sharpen  edge  tools. 

The  following  are  the  various  kinds  of  grindstones,  and 
the  uses  for  which  they  are  best  suited  : 

Ohio,  Nova  Scotia  and  English  stones  are,those  princi- 
pally n?ed,  and  each  of  these  are  cut  to  various  sizes,  and 
have  different  degrees  of  coarseness  and  fineness  of  grit. 
New  Casile  stones  have  a  yellow  color  and  sharp  grit,  the 
fine  sofc  ones  for  grinding  saws  to  gauge  thickness,  and 
the  coarser  for  rougher  work,  as  grinding  sad-irons  and 
springs,  for  face  stones  in  nail  works,  and  for  castings 
(dry  grinding).  Wickersly,  grayish-yellow  color,  for  saws 
and  cullers'  work  generally,  having  a  very  soft  grit  and 
hence  not  liable  to  heat  the  work  and  draw  its  temper. 
Liverpool  (or  Melling"),  of  a  red  color  and  very  sharp  grit, 
for  edge  tools  generally.  Nova  Scotia,  blue  or  yellowish 
gray  color,  being  of  all  grits  from  the  finest  and  hardest 
to  the  coarsest  and  softest,  used  for  general  grinding  as 
well  as  for  machinist  tool  grinding.  Bay  Chaleur  (N.  B.), 
of  a  uniform  blue  color  and  soft  sharp  grit,  for  cutler)'  and 
for  fine  edge  tools.  Independence,  grayish  white  color,  soft 
loose  grit,  for  edge  tools  requiring  a  fine  edge,  and  for  the 
dry  grinding  of  castings.  Huron  (Michigan),  of  a  uniform 
blue  color  and  fine  sharp  grit,  best  suited  for  tools  requir- 
ing a  fine  sharp  edge  as  carpenters'  tools.  It  is  desirable 
that  the  fineness  or  coarseness  of  the  grit  be  uniform 

347 


348  COMPLETE  PRACTICAL  MACHINIST. 

throughout  the  stone,  because  a  hard  spot  will  wear  the 
least  and  become  a  projection,  while  a  soft  one  will  wear 
the  quickest  and  become  a  depression,  either  of  which  is  a 
defect  preventing  the  production  of  true  and  smooth 
grinding. 

A  stone  having  a  coarse  open  grit  will  ctit  the  most 
freely  and  remain  the  most  true,  but  will  not  last  so  long. 

Stones  having  a  close  though  coarse  and  hard  grit  are 
apt  to  become  coated  with  particles  of  the  metal  cut  from 
the  work,  which  is  remedied  by  grinding  a  round  iron  bar 
of  small  diameter,  the  small  area  of  contact  acting  to 
dislodge  the  particles  and  clean  the  stone. 

Grindstones  that  are  used  wet  (as  is  generally  the  case) 
should  be  kept  supplied  with  water  when  in  use,  but  not 
allowed  to  stand. in  water  when  at  rest,  because  the  part 
immersed  will  absorb  water  and  become  the  hardest,  which 
will  cause  it  to  wear  the  least,  thus  throwing  the  stone  out 
of  true. 

Furthermore,  if  the  stone  be  overrun  at  a  quick  speed 
the  side  that  is  water-soaked  becomes  the  heaviest,  and 
this  may  throw  the  stone  sufficiently  out  of  balance  to 
cause  the  unequal  centrifugal  force  generated  at  a  high 
velocity  to  burst  the  stone. 

The  surfaces  of  stones  used  for  sharpening  machinists' 
tools  should  be  kept  as  smooth  as  possible,  while  those  used 
for  removing  metal  or  taking  the  skin  from  metal  or 
similar  work,  where  the  object  is  to  remove  the  metal  as 
quickly  as  possible,  are  what  is  termed  hacked;  that  is,  they 
have  indentations  cut  in  them  with  a  tool  similar  to  a  car- 
penter's adze.  This  hacking  is  usually  performed  most  on 
the  high  parts  of  the  stone,  so  as  to  cause  them  to  wear 
the  most  and  by  this  means  keep  the  stone  true.  This 
class  of  stone  is  usually  of  the  harder  and  coarser  kinds 
of  grit,  the  diameter  of  the  stone  ranging  from  5  to  6  feet, 
and  the  face  from  7  to  12  inches  wide,  and  are  rim  at 
speeds  someti tries  as  great  as  2000  feet  per  minute. 


GEINDSTONE  AND   TOOL   GRINDING.  349 

A  grindstone  should  run  as  true  as  it  is  practicable  to 
\iave  it.  This  is  attained  by  either  fitting  to  the  stone 
truing  devices,  or  truing  the  stone  (at  intervals)  by  hand. 
Sometimes  two  stones  are  so  set  as  to  enable  their  perime- 
ter to  touch,  the  speeds  of  rotation  varying  (or  the  direc- 
tion of  rotation  may  vary)  ;  hence  one  stone  keeps  the 
other  true.  In  this  case  the  best  results  are  obtained 
when  one  stone  only  is  used,  the  other  (which  may  be  a 
small  one)  being  a  truing  stone,  which  is  preferably 
caused  to  traverse  laterally  back  and  forth  across  the 
other  stone  so  as  to  keep  the  face  of  both  stones  at  a  right 
angle  to  their  planes  of'  rotation. 

In  some  cases  grindstones  are  fitted  with  traversing 
rests  which  hold  the  work  and  traverse  it  back  and  forth 
between  two  grindstones.  One  of  the  two  stones  is  speeded 
up  to  about  2000  feet  per  minute  to  perform  the  grinding, 
and  the  other  (usually  of  smaller  diameter)  is  driven  by 
a  gear  wheel  so  as  to  hold  the  work  from  rotating  or 
cause  it  to  rotate  at  a  slow  speed,  as  about  80  feet  per 
minute.  The  smaller  stone  is  so  carried  that  it  may  be 
traversed  to  or  from  the  larger  one,  to  suit  different  thick- 
nesses of  work  and  to  put  on  the  cut. 

For  very  accurate  grinding,  as  for  grinding  the  surfaces 
of  engravers'  plates,  the  grindstone  is,  in  the  best  practice, 
mounted  upon  a  machine  somewhat  similar  to  a  planer — 
the  rotating  stone  occupying  the  position  of  the  planer 
tool.  The  work,  however,  simply  lies  upon  the  table  and 
is  traversed  back  and  forth  beneath  the  stone  by  hand, 
which  obviates  the  spring  that  would  ensue  from  the 
pressure  of  work-holding  devices. 

A  grindstone,  for  tool  grinding,  having  no  truing  device, 
may  be  turned  up  with  a  piece  of  hardened  steel  or  a 
piece  of  gas  or  other  iron  pipe  about  f  inch  in  diameter. 
A  piece  of  iron  is  laid  across  the  grindstone  trough  to 
form  a  rest,  and  the  tool  or  pipe  is  held  at  a  considerable 
f\ngle  to  the  stone,  the  cutting  end  being  well  below  the 
30 


350  COMPLETE  PRACTICAL  MACHINIST. 

surface  of  the  trough.  By  this  means  the  pipe  is  not  liable 
to  take  too  deep  a  cut  or  to  be  wrenched  from  the  hand?, 
as  it  will  give  way  somewhat  to  the  projections  on  the 
stone.  The  tool  should  be  about  4  to  5  feet  long,  and 
should  be  fed  to  its  cut  by  being  slowly  revolved,  which 
will  not  only  feed  it  but  also  keep  the  end  of  the  tool 
square  as  is  necessary.  It  should  be  pressed  firmly  down 
to  the  fulcrum  bar  or  rest  to  prevent  it  from  slipping. 
After  the  stone  is  turned  true  and  to  shape  it  should  be 
smoothed  by  the  edge  of  a  straight  thin  piece  of  sheet- 

Fig.  283. 


iron,  which  .should  be  moved  laterally,  to  prevent  the  edge 
from  grinding,  to  fit  the  projecting  rings  on  the  stone. 

During  this  turning  operation  the  stone  should  be  quite 
dry  and  should  revolve  at  a  slow  speed,  and,  to  prevent 
the  pipe  from  becoming  red  hot,  it  should  be  occasionally 
dipped  in  water. 

The  intermittent  truing  of  a  stone  is,  however,  objec- 
tionable, because  for  the  proper  sharpening  of  tools  the 
stone  should  be  kept  continuously  true,  and  for  this  pur- 
pose we  have  the  device  shown  in  Fig.  283.  It  consists 
of  a  frame  carrying  a  threaded  hardened  steel  roll  bolted 
to  the  trough,  as  in  Fig.  284. 


GRINDSTONE  AND  TOOL  GRINDING. 


351 


The  piece  carrying  the  roll  is  pivoted  below  the  roll, 
hence -by  turning  the  screw  (by  means  of  the  hand  wheel 
shown)  the  roll  is  brought  into  contact  with  the  stone 
surface,  the  thread  crushing  the  projections  on  the  stone 
and  thus  keeping  it  true.  The  friction  between  the  sur- 
faces causes  the  threaded  roll  to  revolve  and  prevents  its 
rapid  wear.  The  advantage  of  this  device  is  that  the 
stone  may  be  kept  true  while  in  constant  use,  and,  as  the 
device  works  with  water,  the  dust  and  dirt  due  to  turning 

Fig.  284. 


with  a  tool  is  avoided  ;  furthermore,  the  stone  is  maintained 
irue  across  its  width,  which  is  highly  advantageous  in 
grinding  machinists'  tools,  especially  those  for  coarse  feeds 
where  it  is  difficult  to  grind  the  nose  of  the  tool  flat  and 
straight.  Since  the  device  can  be  applied  to  or  disengaged 
from  the  grindstone  surface  at  pleasure  it  does  not  unduly 
wear  it  away,  and  indeed  causes,  if  properly  is  seel,  no 
more  wear  than  is  essential  to  keep  the  stone  true.  The 
device  should  be  placed  upon  that  side  on  which  the  stone 
leaves  the  trough  when  rotating. 


5132-  COMPLETE  PRACTICAL  MACHINIST. 

If  a  stone  does  not  run  true  the  tool  will  dip  into  the 
depressions  and  rise  over  the  projections,  rendering  the 
operation  unsteady ;  rounding  the  tool  facet,  and  destroy- 
ing the  flatness  that  is  necessary  to  the  production  of  a 
keen  cutting  edge. 

The  face  of  a  grindstone  for  flat  surfaces  may  be  flat 
across,  or  slightly  rounding,  as  in  Fig.  285,  but  in  no  case 
hollow,  as  in  Fig.  286, for  reasons  which  will  be  explained 
presently. 

If  in  grinding  a  tool  it  is  held  in  such  a  position  that 
the  circumference  of  the  stone  runs  towards  the  operator, 
the  grinding  can  be  performed  quicker  and,  as  a  rule, 

Fig.  285.  Fig.  283. 


better;  but  it  is,  in  many  cases,  quite  dangerous,  because 
the  edge  of  the  tool  is  liable  to  catch  in  any  soft  places 
or  spots  in  the  stone  and  to  be  dragged  from  the  operator's 
fingers;  sometimes  it  will  force  them  down  with  violence 
to  the  tool-rest,  rendering  them  liable  to  injury  by  being 
caught  between  the  rest  and  the  stone.  The  rest  should 
l>e  bolted  firmly  to  the  trough,  and  should  stand  on  such 
gide  of  the  stone  that  the  stone  runs  towards  the  top  of  the 
rest,  this  top  also  being  above  the  level  of  the  centre  of 
the  stone. 

In  determining  upon  which  side  of  the  stone  any  given 
tool  should  be  ground.,  the  workman  takes  into  considera- 


GRINDSTONE  AND  TOOL  GRINDING. 


353 


tion  the  following:  the  shape  of  the  tool,  the  amount  of 
metal  requiring  to  be  ground  off,  and  the  condition  of  the 
grindstone. 

Upon  the  edge  of  a  tool  which  last  receives  the  action 
of  the  stone,  there  is  always  formed  what  is  termed  a 
feather  edge,  that  is  to  say,  the  metal  at  the  edge  does  not 
separate  from  the  body  of  the  metal,  but  clings  thereto  in. 
the  form  of  a  fine  ragged  web,  as  shown  in  Fig.  287,  in 
which  A  represents  a  grindstone  running  in  the  direction 

Fig.  287. 


^f  the  arrow,  B,  and  C  represents  a  tool.  If  now  we  take 
a  point  on  the  circumference  of  the  stone,  as  say  at  F,  it 
should  leave  contact  with  the  tool  at  the  point  denoted  by 
D;  instead  of  doing  this,  however,  the  metal  at  the  ex- 
treme edge  of  the  tool  gives  way  to  the  pressure  and  does 
not  grind  off,  but  clings  to  the  tool,  leaving  a  web,  as 
shown  from  D  to  E ;  whereas,  if  the  same  tool  were  held 
in  the  position  shown  at  G,  the  stone  would  meet  the  tool 
at  the  edge  first,  and  would  cut  the  metal  clear  away  and 


not  leave  a  feather  edge. 

3D 


Now  the  amount  of  the  feather 


354  COMPLETE  PRACTICAL  MACHINIST. 

edge  will  be  greater  as  the  facets  forming  the  edge  stand 
at  a  more  acute  angle  one  to  the  other,  so  that,  were  the 
facets  at  a  right  angle  (instead  of  forming  an  acute  wedge, 
as  shown  in  Fig.  287)  the  feather  edge  would  be  very  short 
indeed.  But  in  all  cases  the  feather  edge  is  greater  upon 
soft  than  upon  hard  metal,  and  is  also  greater  in  propor- 
tion as  the  tool  is  pressed  more  firmly  to  the  stone;  hence 
the  workman  conforms  the  amount  of  the  pressure  to  suit 
the  requirements  by  making  it  the  greatest  during  the 
early  grinding  stage  when  the  object  is  to  grind  away  the 
surplus  metal,  and  the  least  during  the  later  part  of  the 
process,  when  finishing  the  cutting  edge,  and  hence  he 
obtains  a  sharper  tool,  because  whatever  feather  edge 
there  may  be  breaks  off  so  soon  as  the  tool  is  placed 
under  cutting  duty,  leaving  a  flat  place  along  the  edge. 
It  would  seem,  then,  that  faces  which  can  be  ground  in 
the  position  relative  to  the  stone,  shown  in  Fig.  287  (that 
is,  with  the  length  of  the  cutting  edge  lying  across  the 
stone),  and  being  upon  a  tool  of  shape  similar  to  that 
shown  in  the  figure,  should  always  be  ground  with  the 
stone  running  toward  the  cutting  edge,  as  shown  in  the 
figure  at  the  position  denoted  by  G.  This  is  the  case, 
providing  that  the  stone  runs  very  true  and  contains  no 
soft  or  hard  spots  of  sufficient  prominence  to  cause  the 
cutting  edge  to  catch,  which  would,  as  already  stated, 
render  the  operation  dangerous.  These  unfavorable  con- 
ditions, however,  are  always  more  or  less  existent,  under 
average  conditions  and  to  such  an  extent  as  to  forbid  the 
holding  of  the  tool  to  the  stone  with  the  amount  of  press- 
ure necessary  to  remove  such  a  quantity  of  metal,  as  is 
necessary  in  the  earlier  stages  of  the  grinding  operation. 
Furthermore,  if  the  edge  of  the  tool  does  catch  in  the 
stone,  the  damage  to  that  edge,  by  being  ground  away,  is 
very  serious  and  entails  a  great  deal  of  extra  grinding  to 
repair  it,  and  at  the  same  time  incurs  a  rapid  using-up  of 
the  tool.  Another  consideration  is  that  it  is  much  easier 


GRINDSTONE  AND   TOOL   GRINDING.  355 

to  hold  the  tool  steady,  under  ordinary  circumstances,  in 
the  position  shown  at  H,  than  in  that  shown  at  G  ;  and 
with  a  bad  stone  it  is  altogether  impracticable  to  hold  it 
as  at  G.  Here,  however,  another  consideration  occurs,  in 
that  the  surface  of  a  grindstone  is  rarely  level  across  the 
width  of  the  perimeter  of  the  stone,  unless  the  stone  has 
a  truing  device  attached  to  the  frame,  which  at  present  is 
very  largely  the  exception.  As  a  rule  the  face  of  the 
stone  is  made  rounding  in  its  width  because  there  is  the 
most  wear  in  the  middle,  and  it  is  very  undesirable  to 
have  the  stone  hollow  across.  Suppose,  for  example,  that 
we  have  a  stone  that  is  hollow,  as  in  Fig.  284,  and  one 
that  is  rounding  across  the  perimeter,  as  in  Fig.  285;  then 
to  grind  such  a  tool  as  is  shown  in  Fig.  2$7,  as  say  a  plane 
blade,  we  may  move  it  slowly  across  the  width  of  the 
stone,  and  the  highest  part  of  the  stone  will  act  upon  all 
parts  in  the  width  of  the  blade;  but  we  cannot,  by  any 
method,  grind  such  a  tool  upon  the  hollow  stone  without 
leaving  the  cutting  edge  rounding  in  its  length,  or  else 
leaving  the  ground  facet  rounding  in  its  width  or  depth, 
the  latter  being  the  case  when  the  cutting  edge  is  held  in 
line  with  the  plane  of  rotation  of  the  stone. 

In  grinding  pointed  tools,  as  centre-punches,  scribers, 
etc.,  grooves  are  very  apt  to  be  worn  in  the  stone  unless 
the  tool  be  moved  back  and  forth  across  the  stone  face,  or 
held  at  an  angle  to  the  plane  of  rotation. 

The  reason,  when  truing  up  a  stone  by  hand,  for  leaving 
it  rounding  across  its  face  is  that  the  middle  is  more  used 
than  the  edges,  and  the  wear  is,  therefore,  correspondingly 
greater  in  the  middle.  This  causes  the  stone  to  gradually 
wear  first  flat  across  and  then  hollow,  necessitating  that  it 
be  turned  up  though  it  may  run  true. 

When  a  stone  is  uneven  across  its  width,  the  operator, 
no  matter  which  side  of  the  stone  he  is  using,  holds  the 
length  of  the  cutting  edge  of  the  tool  at  an  angle  to  the 
width  of  the  stone,  as  shown  in  Fig.  288,  placing  the  tool 


356 


COMPLETE  PRACTICAL  MACHINIST. 


in  the  most  level  part  of  the  grindstone  surface.  By  doing 
this  he  effects  two  objects :  first,  he  obtains  a  level  spot 
upon  the  stone  more  readily,  and  secondly,  he  diminishes 
the  formation  of  a  feather  edge.  The  first  is  because  it  is 
obvious  that,  in  removing  a  given  amount  of  metal,  there 
will  be  more  abrasion  upon  the  stone  in  proportion  as  the 
operating  area  of  the  stone  is  diminished,  hence  the  \\ork- 

Fig.  238. 


r,?an  ^rlects  the  highest  part  of  the  stone  whereon  he  can 
find  a  suitable  surface,  and  by  moving  the  tool  across  the 
face  wears  down  the  asperities  (while  he  is  roughing  out 
the  tool)  so  as  to  obtain  as  smooth  a  surface  as  possible 
for  finishing  process.  If  he  held  the  tool  still  instead  of 
giving  it  lateral  motion,  it  would  grind  away  in  undula- 
tions or  grooves  conforming  themselves  to  those  on  the 
•ibradiug  surface  of  the  stone,  and  the  roughing  process 


GRINDSTONE  AND  TOOL  GRINDING. 


357 


Fig.  289. 


ivould  have  but  very  little  effect  towards  leveling  the 
stone.  Referring  now  to  the  second  advantage  named. 
it  will  be  readily  observed  that,  if  he 
held  the  length  of  the  cutting  edge 
in  a  line  with  the  revolutions  of  the 
V  stone,  as  in  Fig.  289,  there  would  be 
\  no  tendency  to  leave  a  feather  edge, 
except  at  the  corner  of  the  edge 
-where  the  stone  leaves  contact  with 
the  tool,  and  this  would  be  of  little 
or  no  consequence.  The  question 
naturally  arises,  then,  why  not  grind 
the  tool  in  that  position,  which  would 
require  a  very  small  flat  or  smooth 
space  in  the  width  of  the  stone  and 
would  avoid  the  formation  of  a 
feather  edge.  The  answer  to  this  is 
that  it  would  be  very  difficult  to  grind  the  surface  of  the 
tool  level,  as  will  be  perceived  from  the  side  view  of  the 
operation  as  shown  in  Fig.  290,  in  which  A  represents 

Fig.  290. 


Jf. 


358 


COMPLETE  PRACTICAL  MACHINIST. 


the  tool  enlarged  so  as  to  make  the  engraving  clear.  To 
bring  the  whole  length  of  the  cutting  edge  to  bear  upon 
the  stone  it  is  necessary  to  move  the  tool  from  C  to  D, 
and  from  B  to  E,  as  denoted  by  the  dotted  arcs  at  D, 
E;  and  if  during  this  movement  the -tool  remains  ati 

Fig.  291. 


instant  too  long  in  either  of  the  positions  indicated  by 
the  dotted  lines,  G,  H,  or  at  any  time  during  the  motion, 
a  hollow  spot  will  be  ground  upon  the  tool  at  the  point 
of  contact  between  the  stone  and  the  tool;  furthermore 
the  grinding  operation  is  not  very  accessible  to  the  eye 
and  hence  any  irregularities  are  not  very  easily  corrected. 


GRINDSTONE  AND   TOOL   GRINDING.  359 

For  these  reasons  it  is  impracticable  to  grind  in  this  posi* 
tion  any  cutting  edge  requiring  to  be  a  straight  line  and 
having  sufficient  length  to  render  much  motion  in  the 
direction  of  D,  E,  a  necessity.  Furthermore  it  is  very 
difficult  to  hold  a  tool  steadily  in  position  shown  in  Fig. 
290,  and  as  a  consequence  no  satisfactory  result  can  be 
attained  unless  by  the  aid  of  a  device  whereon  to  rest 
the  hand;  such  a  device  is  called  a  rest  and  is  shown  in 
Fig.  291.  Now  suppose  we  have  a  tool  of  the  form  shown 
at  C  in  Fig.  291,  requiring  to  be  ground  on  the  faces,  A 
and  B;  then  it  is  evident  that  A  can  only  be  ground  with 
the  body  of  the  steel,  C,  out  of  the  way  of  the  body  of  the 
stone,  and  hence  in  the  position  shown  in  the  figure,  in 
which  position  the  tool  may  be  held  and  pressed  firmly  to 
the  stone.  It  is  necessary,  however,  to  rest  the  hand  upon 
the  rest  and  hold  the  tool  exactly. in  the  position  shown, 
so  that  if  the  tool  catches  in  the  stone  and  is  forced  from 
the  hand  it  will  not  carry  the  fingers  with  it,  and  wound 
them  by  jamming  either  against  the  stone  or  the  rest,  or 
force  them  between  the  two.  It  would  seem  advisable  to 
rest  the  tool  upon  the  rest  without  the  intervention  of  the 
hand,  but  such  is  not  the  case,  because  the  operator  would 
not  have  sufficient  control  over  the  tool  and  it  would 
almost  assuredly  catch  in  the  stone.  By  interposing  the 
hand  between  the  tool  and  the  rest,  the  sense  of  feeling  is 
brought  into  play,  guiding  the  operator  just  how  to  hold 
the  tool  to  prevent  its  catching  in  the  stone  and  admonish- 
ing him  when  the  conditions  possess  any  elements  of 
danger,  which  become  instantly  known  from  any  difficulty 
in  holding  the  tool  steady  against  the  grip  of  the  stone  or 
from  a  disposition  of  the  upper  edge  of  the  tool,  which 
the  stone  meets,  to  turn  in  towards  the  stone. 


CHAPTER    XVIII. 

LINING   OR   MARKING   OUT  WORK. 

WHEN  work  is  got  out  by  means  of  special  machines, 
or  in  special  jigs,  chucks,  or  appliances,  it  is  generally 
unnecessary  to  denote  its  shape  or  dimensions  by  lines. 
But  in  large  work,  such  as  marine  engine  work,  there  are 
rarely  a  sufficient  number  made  of  precisely  one  pattern 
to  make  it  pay  to  get  these  special  machine  tools  or  appli- 
ances, hence  the  work  requires  to  be  marked  out  by  lines. 

So  likewise  in  the  case  of  repairs  for  all  save  the  small 
class  of  machines,  such  as  sewing  machines,  the  work  re- 
quires to  be  lined  or  marked  out  because  the  original  di- 
mensions must  be  varied  to  accommodate  the  wear  of  the 
parts. 

In  the  general  machine  shop  the  lining  out  of  work 
forms  an  important  part  of  the  manipulation.  In  the 
case  of  a  very  simple  piece,  such  as  say  a  square  bar,  tho 
lining  maybe  dispensed  with  because  the  lineal  measuring 
rule  will  demonstrate  whether  the  work  is  large  enough  to 
permit  of  being  cut  to  the  required  dimensions.  But  in 
irregular  shaped  bodies  it  is  necessary  to  mark  out  the 
work  by  lines  which  serve  to  set  the  work  true  on  the 
machine  tools,  and  to  denote  the  dimensions  to  which  the 
work  should  be  cut  to  reduce  it  to  its  required  form. 

In  giving  examples  of  the  processes  of  lining  out  work, 
it  has  been  thought  best  to  let  them  be  of  the  various 
parts  of  an  engine,  and  with  this  view  each  part  of  a 
simple  engine  that  could  be  utilized  to  represent  a  certain 
class  of  work  has  been  selected. 
360 


LINING   OR  MARKING    OUT   WORK.  361 

First,  however,  let  it  be  noted  that  while  the  principles 
Applied  in  marking  or  lining  out  are  the  same  as  those 
involved  in  mechanical  drawing,  yet  the  application  is  en- 
tirely different.  The  draughtsman  may  obtain  his  centres 
aud  lines  for  one  view  or  side  of  a  piece  by  projecting  those 
from  another  view  or  side  of  the  work,  whereas  in  mark- 
ing out  the  work  the  lines  must  be  transferred  from  one 
side  of  it  to  the  other ;  or,  in  many  cases,  the  lines  on  one 
side  may  be  entirely  different  from  those  on  the  other,  and 
yet  require  to  be  definitely  located  with  reference  to  the 
same. 

The  lining  out  of  work  requires  also  to  be  more  accu- 
rately performed  than  do  the  Hues  on  a  drawing,  because 
the  variation  to  an  amount  of  the  thickness  of  a  line  may 
involve  the  spoiling  of  a  piece  of  work  or  entail  a  great 
deal  of  extra  labor  in  fitting  the  parts  together.  Sup- 
pose, for  example,  a  block  and  a  strap  requiring  to  be 
fitted  together  are  marked  by  lines:  the  block  being 
marked  the  thickness  of  the  line  too  large,  and  the  strap 
the  thickness  of  the  line  too  narrow.  When  the  work 
comes  to  be  fitted  there  will  be  the  thickness  of  the  two 
lines  to  file  away  to  make  the  strap  fit  to  the  block. 
Furthermore,  unless  lining  out  or  marking  out  work  by 
lines  be  very  accurately  performed,  an  element  of  uncer- 
tainty is  engendered,  and  the  machine  operators,  instead  of 
cutting  away  the  surface  metal  to  split  the  line,  will  leave 
the  lines  in  as  evidence  that  they  have  not  removed  too 
much  metal,  and  as  a  result  the  filling  operations  are 
again  increased. 

A  marker-out,  as  the  operative  is  termed,  should  not 
only  be  one  capable  of  great  exactitude  in  his  measure- 
ments, but  should  also  be  an  expert  workman  at  the  lathe, 
vise,  planing  machine,  and  drilling  machine  ;  because  it  is 
by  his  lines  that  the  work  is  chucked,  and  hence  he  should 
know  the  very  best  method  of  chucking  or  holding  the 
work  in  each  of  the  machines.  Furthermore  a  line  over 
31 


36$  COMPLETE  PRACTICAL   MACHINIST. 

and  above  those  necessary  to  define  "the  outline  of  the 
work  is  often  necessary  for  use  as  an  assistance  and  guide 
in  chucking  it.     Upon  the  truth  of  this  lining,  in  many 
cases,  will  the  truth   of  the  finished  work   depend,  and 
even  in    those  instances  where  the  method  of  chucking 
will  correct  any  inaccuracy  in  the  marking-out,  the  use- 
fulness of  the  latter  is  almost  entirely  destroyed,  because 
the  lines  will  become  entirely  removed  on  one  side,  and 
left  fully  in  on  the  other  side  of  the  work.     If,  however, 
the  marking-out  is  performed  reasonably  true,  one  of  its 
main  elements  of  usefulness  consists  in  that  it  denotes  if 
there  is  sufficient  excess  of  metal  upon  the  piece  of  work 
to  permit  of  its  being  cleaned  up  all  over.     But  if  there 
is  any  one  part  of  the  work  scant  of  metal,  as  is  sometimes 
the  case  in  forgings  of  unusual  and  irregular  form,  the 
marking-out  requires  to  be  very  true,  and  may  be  made  to 
just  save  a  piece  of  work  that  otherwise  would  have  been 
spoiled.     By  accommodating  the  marking  to  some  spot  or 
place  in  the  work,  which  will  only  come  up  to  the  full  size 
by  throwing  the  whole  of  the  rest  of  the  lines  towards  the 
opposite  side  of  the  work,  a  costly  piece  of  forging  may 
be  saved  from  the  scrap  heap.     And  again,  in  castings 
where  the  surface  appears  spongy,  showing  the  presence 
of  air  holes  beneath  the  surface,  or  in  forgings  where  the 
Bin-face  may  indicate  that  a  weld  is  not  perfect  upon  one 
bide,  the  whole  of  the  marking-oil  I  should  be  performed 
with  a  view  to  take  off  as  much  metal  as  possible  on  the 
faulty  side.     In   other  work   there   may  be  a  part  very 
difficult  to  turn  or  plane  on  account  of  the  conformation 
of  the  job;  in  which  case  the  marker-out,  foreseeing  such 
to  be  the  case,  will  so  place  the  lines  as  to  give  as  little  to 
come  off  that  particular  place  as  possible,  disregarding 
the  excessive  heavy  cut  or  amount  of  metal  which  it  may 
be  necessary  to  cut  off  other  and  more  accessible  parts  of 
the  work.     There  are  many  other  considerations,  whicl? 
need  not  be  here  enumerated,  all  tending  to  show  that  a 


LINING   OR  MARKING   OUT  WORK. 


363 


marker-out  should  be  a  master  hand  at  the  various 
branches  of  his  business,  and  possess  much  judgment  and 
experience. 

TO   MARK   AN    ELLIPSE. 

Draw  the  line  A  B,  Fig.  292,  equal  to  the  required 
length  of  the  ellipse.  Bisect  it  by  the  line  C  D,  which 
must  stand  ut  a  right  angle  to  it,  be  equal  in  length  to  the 
required  width  of  the  ellipse,  and  extend  an  equal  distance 
on  each  side  of  it.  With  a  radius  of  one-half  the  re- 
quired length  of  the  ellipse  mark  from  C  (or  D)  as  a 
centre  the  arc  F  H  G,  and  at  the  points  of  intersection  of 
this  arc  with  the  line  A  B  (that  is  at  F  and  G)  drive  in 
two  pins.  Drive  in  a  pin  at  C  and  pass  a  piece  of  fine 

Fig.  292. 


twine  around  the  pins  at  A  F,  G,  and  C,  and  tie  it  tight 
enough  to  prevent  any  slackness. 

Remove  the  pin  at  C  (which  is  only  employed  for  con- 
venience in  tying  the  twine  to  its  proper  length  without 
being  under  tension  or  having  any  slack).  Take  a  pencil : 
move  it  outwards  from  the  pins  F  G  until  the  twine  is 
drawn  straight,  then  sweep  it  around  and  its  point  will 
describe  an  ellipse.  In  the  Fig.  the  pencil  is  shown  at 
P,  the  position  of  the  twine  when  the  pencil  is  at  that 
point  being  denoted  by  the  dotted  lines. 


364 


COMPLETE  PRACTICAL  MACHINIST. 


The  pencil  must  be  held  vertical  while  tracing,  otherwise 
the  figure  will  not  be  true.  To  assist  this  a  piece  of  wood 
may  be  laid  and  slid  on  the  surface,  on  which  the  ellipse 
is  traced,  and  the  pencil  held  against  the  piece  of  wood. 

TO   FIND    POINTS    THROUGH    WHICH    THE    CURVE   OF   AN 
ELLIPSE   MAY    BE   DRAWN. 

Let  A  B,  CD,  Fig.  293,  be  the  respective  diameters 
of  the  curve:  mark  the  parallelogram  L  M  N  O  meeting 
the  ends  of  the  axes  as  at  A  B,  C  D.  Divide  A  L,  A  N, 
S  M,  and  B  O  into  any  number  of  equal  parts,  and 
number  them  as  in  the  Figure.  Divide  A  S  and  D  S 
into  four  equal  parts :  numbering  them  from  the  ends  to- 
wards the  centre.  From  the  points  of  division  in  A  L 
and  B  M  draw  lines  to  the  point  C,  and  from  the  points 
of  division  in  B  O  and  A  N  draw  lines  to  the  point  D. 


N  D  O 

From  the  point  D  draw  lines  passing  through  the  points 
1,  2,  3  in  A  S  to  intersect  the  lines  1,  2,  3  drawn  from  the 
points  of  division  on  A  L ;  also  from  point  D  through  D 
S  to  intersect  the  lines  from  B  M.  These  points  of  inter- 
section are  points  in  the  curve. 

From  C,  through  the  divisions  1,  2,  3  on  S  A  and  S  B, 
draw  lines  to  intersect  lines  1,  2,  3  drawn  from  A  N  and 
B  O:  the  points  of  intersection  being  points  through 
which  the  other  half  of  the  curve  may  be  drawn. 


LINI^7G   OR  MARKING   OUT   WORK. 


365 


The  tools  employed  by  the  marker-out  are  as  follows : 
Fur  plugging  holes  so  that  compass  points  may  be  sup- 
ported withiu  the  hole,  disks  of  lead  such  as  are  shown  in 
Figures  294  and  295  are  employed.  They  may  be 
stretched  larger  or  compressed  smaller  in  diameter  to  suit 
any  required  size  of  hole,  by  a  few  blows  with  the 
hand -hammer,  and  the  lead  will  conform  itself  to  the 
uneven  shape  of  the  hole,  and  will  therefore  hold  fast  and 
not  be  liable  to  move  ;  and,  furthermore,  a  few  such  blows 
will  deface  any  lines  which  may  have  been  made  upon 
the  face  of  the  lead  in  service  upon  a  previous  piece  of 
work.  Again  it  may  be  necessary  to  first  mark  a  centre 
line,  arid  subsequently  other  lines ;  and  then  drawing  a 
wet  finger  across  the  old  lines  on  the  lead  will  dull  them, 
while  the  newly  made  ones  will  be  bright,  and  thus  remain 
distinct.  For  holes  that  have  been  trued  out,  similarly 
shaped  pieces  of  sheet  brass  may  be  used,  the  form  shown 
in  Fig.  295  being  for  the  larger,  and  that  shown  in  Fig. 

Fig.  294.  Fig.  295. 


294  for  the  smaller  sized  holes  ;  these  brass  pieces  may  be 
filled  up  very  true,  and  have  a  centrepunch  mark  in  their 
exact  centre,  thus  obviating  the  necessity  of  finding  the 
centre  at  each  time  of  using. 

For  use  on  holes  of  comparatively  large  dimensions, 
31  •- 


366 


COMPLETE  PRACTICAL   MACHINIST. 


that  is  to  say,  above  4  inches  in  diameter,  the  centre  piece 
shown  in  Fig.  296  is  very  convenient.  A  represents  a 
piece  of  wood,  and  B,  a  small  piece  of  tin  or  sheet  iron, 
having  its  corners  bent  up  so  that  they  may  be  driven  into 
the  wood  and  thus  made  fast  in  position  to  receive  the 
Fig.  296.  Fig.  297. 


centre.  Such  a  centre  is  very  easily  and 
readily  made,  and  may  be  used  on  rough  or 
finished  work.  If  the  surface  of  the  work 
upon  which  either  of  these  centres  is  used 
is  flat,  the  ends  of  the  centres  must  of  course 
be  also  flat;  and  in  the  case  of  the  last  de- 
scribed, a  piece  of  paper,  leather,  or  other 
material  may  be  inserted  in  one  end  to  make  up  any 
small  deficiency  in  the  size.  The  centrepunch  used  for 
marking-out  should  be  as  shown  in  Fig.  297,  the  object 
of  making  its  diameter  so  small  toward  the  point  being 
that  it  shall  not  obstruct  a  clear  view  of  the  line.  A 
heavier  centrepunch  may  of  course  be  employed  to  in- 
crease the  size  of  the  centrepunch  marks  when  the  same 
is  necessary.  The  hammer  should  also  be  a  small  one, 
weighing  about  one-quarter  of  a  pound,  with  a  ball  face 
to  efface  any  centrepunch  marks  erroneously  marked  or  to 
be  dispensed  with,  an  ordinary  hammer  being  employed 
to  perform  any  necessary  operation  other  than  the  simple 
marking-out. 


LINING   OR  MARKING   OUT   WORK.  367 

TO    DIVIDE   A  STRAIGHT   LINE   INTO   TWO  EQUAL   PARTS. 

From  each  end  of  the  line  we  describe  arcs  of  circles, 
as  at  F  in  Fig.  298,  adjusting  the  compasses  so  that  the 
two  arcs  meet  at  the  given  line,  as  shown  in  the  figure. 
Fig.  298.  B?   then   resting   the 

compass  points  at  the 
.    coincidence  of  the  arcs 

r  \ 

F,  and  describing  the 
arcs   B   C,  the  latter 
will  cut  the  ends  of 
the  line,  as  shown  in  the  figure. 

TO    DIVIDE   A    STRAIGHT    LINE    INTO    A    NUMBER   OF 
EQUIDISTANT   POINTS. 

Let  A  B,  in   Fig.  299,  represent  a  line  to  be  divided 
into  10  equal  divisions.     With  a  pair  of  compasses  set 

Fig.  299. 
AC        DJSF-GJJJTJ'XJErJl 

L_i_j__i_.A  y  t  f  (  (  > 

/     \    \    (        !    )    A    V 

S          Jt      f)      I3  M      N      0  V      V 

as  near  as  may  be  to  ^  the  length  of  the  line  measured 
upon  a  finely  divided  rule,  and  starting  from  the  end 
A  of  the  line  step  off  on  the  line,  and  mark  above  the 
line  the  arcs  C  D  E  F  G.  From  B  step  off  and  mark 
the  arcs  H  I  J  K  L,  and  if  the  compasses  are  correctly 
set,  G  and  L  will  join  at  their  point  of  coincidence  with 
the  line.  If  not,  mark  a  point  as  shown  in  the  figure, 
upon  the  line  and  midway  between  G  and  L.  Since  G 
and  L  overlap  each  other  the  compass  points  are  too  far 
apart,  hence  they  must  be  corrected,  which  may  best  be  done 
when  the  error  is  a  very  fine  one  by  oilstoning  them  on 
the  outside.  With  the  corrected  compasses  and  from  the 
dot  as  a  centre,  step  off  upon  the  line  divisions  P  O  R. 
From  the  end  A  of  the  line  step  off  divisions  S  T,  and 
midway  between  S  and  T  upon  the  line  mark  another  dot, 


368  COMPLETE  PRACTICAL  MACHINIST. 

and  these  two  dots  will  be  correct  points  of  division,  not- 
withstanding that  the  compass  points  are  shown  in  both 
cases  to  be  incorrectly  set.  The  want  of  coincidence  of  T 
R,  which  do  not  meet  at  their  point  of  coincidence  with 
the  line,  shows  the  compass  points  to  be  too  near  together, 
hence  in  this  case  those  points  must  be  corrected  by  oil- 
stoning  them  on  the  inside.  This  being  done  from  the  dot 
at  G  L  as  a  centre,  step  off  on  the  line  the  divisions  in  M 
N  O  and  mark  the  arcs,  then  from  the  end  B  of  the  line 
mark  off  V  U,  and  midway  between  O  U  is  another  point 
of  division.  The  error  shown  to  exist  in  the  compass 
point  being  again  corrected  we  may  from  these  four  points 
mark  off  the  intermediate  ones.  By  this  method  the 
division  may  be  proceeded  with  while  correcting  the  com- 
pass points.  If,  however,  the  number  of  divisions  is  an 
odd  one  instead  of  an  even  one  as  in  this  example,  the 
compasses  must  be  stepped  from  each  end  of  the  line  as 
before,  and  adjusted  until  the  space  forming  the  middle 
division  is  equal  to  the  distance  at  which  the  compass 
points  are  set. 

But  suppose  it  be  required  that  the  points  of  division 
vary  in  regular  order  as  in  the  case  of  a  piece  requiring 
say  60  holes  in  a  given  length,  the  distance  between  two 
given  holes  being  1.57  inches,  and  the  two  next  1  inch, 
and  so  on  continuously. 

The  total  number  of  holes  must  in  this  case  be  an  even 
one;  hence  we  mark  off,  by  the  rules  already  given,  one> 
half  of  that  total  number,  making  them  equidistant  all 
round  the  circle  or  circumference,  as  the  case  maybe, 
which  points  will  represent  the  distance  apart  of  the  holes 
that  are  widest  apart,  as  the  holes,  A,  B,  0,  D,  and  E,  in 
Fig.  300,  amounting  in  our  example  to  30  in  number. 
We  then  set  our  compasses  to  the  required  distance  apart 
of  the  two  holes  nearest  together;  and  commencing  at  A 
in  Fig.  300,  we  mark  the  centre  for  the  hole,  F,  and  from 
the  centre  of  the  hole,  B,  the  centre  of  the  hole,  G,  and 


LINING   OR  MARKING   OUT   WORK.  369 

so  on,  continuing  all  round  the  circle,  but  taking  care  to 

mark  the  new  centre  in  each  case  in  advance  of  or  behind 

the  points,  A,  B,  C,  etc.,  according  to  the  manner  in  which 

Fig.  300. 


<  1 

x  1.57.    x  1  * 

0 

$ 

0 

*i 

i,9 

ty 

O 

$ 

O 

A 

B 

£ 

K 

C 

D 

A 

the  first  of  the  holes  nearest  together  was  marked.  Thus 
in  Fig.  300,  the  points,  F,  G,  H,  and  I,  are  marked  to  the 
right,  in  each  case,  of  the  points  from  which  they  were 
struck. 

Before  proceeding  to  mark  out  a  piece  of  work,  it  should 
be  roughly  measured  so  as  to  ascertain,  before  having  any 
work  done  to  it,  that  it  will  clean  up.  The  square  should 
also  be  applied  to  see  if  it  is  out  of  square,  and  thus  to 
find  out  if  it  is  necessary  to  accommodate  the  marking  out 
to  any  particular  part  that  may  be  scant  of  material  (or 
stock,  as  it  is  often  termed).  The  surface  of  the  work 
should  also  be  examined  ;  so  that,  if  any  part  of  it  is  de- 
fective, the  marking  off  can  be  performed  with  a  view  to 
remedying  the  error,  whether  of  excess  or  defect.  Now 
let  us  mark  off  a  block,  say  of  12 
inches  cube,  and  we  shall  find  that 
we  must  not  mark  it  out  all  over 
until  one  of  the  faces  has  been 
planed  up.  Suppose,  for  instance, 
we  mark  it  out  as  shown  in  Fig. 
301.  The  inside  lines  on  faces  A 
and  B  are  the  marking-ofF  lines. 
If,  then,  we  cut  off  the  metal  to  the 
lines  on  A,  we  shall  have  removed  the  lines  on  B,  and 
vice  versa;  and  there  is  no  manner  or  means  of  avoiding 
the  difficulty,  save  as  follows:  We  may  mark  off  one  face, 
and  let  the  block  be  cut  down  to  the  lines,  before  mark- 


370 


COMPLETE  PRACTICAL  MACHINIST. 


ing  the  other  face;  or  we  may  have  a  surfacing  cut  taken 
off  one  face,  and  then  perform  the  whole  of  the  marking 
off  at  one  operation.  The  latter  plan  is  preferable,  be- 
cause it  gives  us  one  true  face  to  work  from  in  marking 
off,  and  obviates  the  necessity  of  having  to  prevent  the 
rocking  of  the  work  upon  the  marking-off  table  by  the 
insertion  of  wedges,  which  is  otherwise  very  commonly 
requisite.  It  is  preferable,  then,  upon  all  work  easily 
handled  and  chucked,  and  in  which  the  lining  off  must 
be  performed  on  more  than  one  face,  to  surface  one  face 
before  performing  the  marking  out ;  and  supposing  our 
block  to  have  one  face  so  surfaced,  we  will  proceed. 

We  first  well  chalk  the  surface  of  the  work  all  round 
about  where  we  expect  the  lines  to  come,  which  is  dose  to 
make  the  lines  show 

•  30'2' 


B 


J 


plainly;  we  then  place 
the  work  upon  the 
table  with  the  surfaced 
face  downward  ;  and 
placing  a  rule  along- 
side of  it,  we  set  the 
scriber  of  the  surface 
gauge  so  as  to  take  off 
the  necessary  amount 
from  the  top,  as  shown 

in  Fig.  302  (A  being  the  plated,  and  mark  the  line,  B, 
around  all  four  faces 
of  the  work.  We  then 
turn  the  work  on  the 
plate  so  that  the  true 
face  stands  perpen- 
dicularly, setting  it 
true  by  wedging  it,  so 
that  a  square  being 
placed  with  the  back 
to  the  face  of  the  table,  and  the  blade  against  the  surfaced 


Fig.  303. 

F 

I 

jl 

C 

*-JZ    —  * 

^~ 

E 
~| 

A 


OR  MARKING   OUT  WORK. 


371 


Fig.  304. 


face  of  the  work,  the  latter  will  stand  true  with  the  square 
blade,,  as  shown  in  Fig.  303.  A  being  the  marking-off 
table,  B  the  square,  and  C  the  surfaced  face  of  the  work. 
We  then  (with  the  scribing  block)  mark,  across  the  sur- 
faced face  of  the  work,  two  lines,  12  inches  apart,  and  of 

equal  distance  from  the 
top  and  bottom  faces  of 
the  work,  as  shown  in  Fig. 
304,  at  A  and  B.  Our 
next  operation  is  to  mark 
off,  on  the  surfaced  face 
of  the  work,  two  more 

1  lines,    standing    at    right 

angles  to  the  lines  A  and  B 

in  the  above  figure ;  so  that  the  surfaced  face  will  have 
four  lines  upon  it.  These  last  two  lines  we  mark  without 
moving  the  work,  by  placing  a  square  with  its  back  rest- 
ing upon  the  table,  the  square  blade  standing  vertically 
and  at  the  necessary  distance  from  the  edge  of  the  block, 
as  shown  in  Fig.  305,  A  and  B  being  the  lines  drawn  by 
the  scribing  block,  and  C  C  the  square  in  position  to  draw 
one  of  the  necessary  per- 
pendicular lines,  the  other, 
shown  at  D,  being  sup- 
posed to  have  been  marked 
from  the  square  while  it 
was  turned  around.  Here, 
then,  we  have  the  lines  for 
four  of  the  faces,  marked 
upon  a  face  already  sur-  | 
faced  to  the  size,  thus  dis- 
posing of  five  out  of  the  six  faces  :  and  since  the  line  for 
the  sixth  face  stands  diametrically  opposite  to  the  sur- 
faced face,  the  latter  has  only  to  be  kept  down  evenly 
upon  the  table  of  the  planer  to  insure  the  sixth  face  being 
cut  true ;  after  which,  and  when  each  of  the  remaining 


Fig.  305. 


1 


372  COMPLETE  PRACTICAL  MACHINIST. 

four  sides  is  chucked  to  be  operated  on,  we  have  a  true 
face  to  place  next  to  the  angle  plate,  and  a  true  one 
against  which  to  apply  the  square  to  test  if  the  work  is 
held  true.  Thus  we  find  that  the  surfaced  face  of  the 
work,  when  placed  on  the  face  of  the  marking-off  table 
and  on  the  face  of  the  planer  table,  becomes  a  gauge  by 
which  (with  the  aid  of  the  square)  all  the  other  faces  may 
be  marked  or  cut  true. 

It  is  obvious  that,  had  either  one  of  the  faces  of  the 
work 'been  faulty,  we  might  have  taken  off  it  as  much 
metal  as  possible,  leaving  only  sufficient  to  clean  up  the 
face  diametrically  opposite.  It  often  happens  that  an  ap- 
parently faulty  face  shows  to  more  disadvantage  by  having 
a  cut  taken  off  it;  especially  is  this  the  case  in  iron 
castings,  in  which  there  may  be  more  air  holes  beneath 
than  upon  the  surface,  which  defect  may  be  sufficiently 
serious  to  spoil  the  work.  It  is  therefore  preferable  to 
take  the  first  or  surfacing  cut  off  the  defective  face,  so 
that  the  degree  of  defect  may  be  discovered  before  even 
the  marking-out  is  performed. 

The  lines  being  marked,  our  next  procedure  is  to  make 
light  centrepunch  marks  at  short  intervals  along  them,  so 
that,  if  the  lines  become  obliterated  through  handling  the 
work,  the  centrepunch  dots  will  serve  instead.  These  dots 
should  be  marked  very  true  with  the  lines,  otherwise  they 
destroy  the  truth  of  the  marking ;  because  the  machine 
operator,  in  setting  the  work  in  the  machine,  is  usually 
guided  by  the  dots. 

By  this  method  we  may  mark  off  any  body  whose  out- 
line is  composed  of  straight  lines,  and  whose  diametrically 
opposite  faces  are  parallel,  no  matter  what  the  length, 
breadth,  and  thickness  of  the  body  may  be.  It  is  not, 
however,  at  all  times  desirable  to  perform  all  the  marking- 
out  at  one  operation.  Suppose,  for  example,  our  work  had 
been  a  piece  of  metal  1  foot  square  and  I  of  an  inch  thick : 
were  we  to  face  off  one  of  the  broad  faces  before  marking' 


LINING    OR  MARKING    OUT   WORK.  373 

off,  we  should  find  it  very  difficult  to  set  our  work  upon 
the  rough  edge,  and  set  it  true  to  the  square,  as  shown  in 
Fig.  303;  whereas,  were  we  to  face  off  one  of  the  edges 
first,  we  have  I  of  an  inch  only  against  which  to  try  the 
square  when  setting  the  planed  edge  perpendicular.  In 
such  a  case,  therefore,  it  is  best  not  to  mark  off  the  edges 
until  the  body  of  the  work  is  cut  to  the  required  thick- 
ness. 

To  mark  off  a  body  such  as  shown  at  B  in  Fig.  306, 
which  represents  an  engine  guide  bar,  one  face  must  either 
be  first  trued  up.  or  the  mar  king-off  must  be  performed  at 
two  separate  operations.  The  belter  plan  is  for  the  marker- 
off  to  examine  the  bar  as  to  size,  and  have  one  face  planed 
off.  If  either  face  appears  defective,  it  should  be  the  first 
planed.  If  the  bar  appears  sound  all  over,  an  outside 
edge  face  of  the  bar  should  be  the  one  to  be  planed  off 
preparatory  to  marking-off ;  and  in  setting  it  to  surface  it, 
care  should  be  taken  to  set  it  true  with  the  top  and  bottom 
faces,  if  they  are  parallel  to  each  other ;  and  if  not,  to 
divide  whatever  difference  there  may  be  between  them. 
The  bar  may  then  be  placed  upon  the  marking-off  table  in 
the  position  shown  in  Fig.  306,  A  being  the  marking-off 

Fig.  306. 


plate,  B  the  guide  bar,  C  C  pieces  of  wood  to  lift  the  bar 
off  the  plate.  By  means  of  small  thin  wedges,  the  planed 
face,  B,  of  the  bar,  is  set  at  a  true  right  angle  to  the  sur- 
face of  the  plate,  and  tested  by  a  square.  The  next  oper- 
ation is  to  mark  off  the  top  or  uppermost  face,  and  the 
question  here  arises :  Shall  it  be  so  marked  that  there  will 
be  an  equal  amount  of  metal  taken  off  the  top  and  bottom 
32 


374-  COMPLETE  PRACTICAL  MACHINIST. 

faces,  or  otherwise  ?  First,  then,  since  the  quality  of  the 
metal  is  the  best  towards  the  surface,  it  is  a  consideration 
to  take  off  as  little  as  possible,  so  as  to  leave  a  hard 
wearing  surface ;  this  may  appear  a  small  matter,  but  it 
is  always  right  to  gain  every  superiority  attainable  without 
cost.  Therefore,  all  other  things  being  equal,  we  should 
prefer  to  take  as  little  metal  off  the  top  face  as  would  be 
sufficient  to  make  it  true,  and  should  therefore  mark  it 
out  with  that  view.  Here,  however,  another  consideration 
arises,  which  is  that  the  outline  of  the  bottom  face  is  not 
straight,  and  cannot  therefore  be  planed  lengthways  from 
the  centre  of  the  bar  to  the  ends  at  one  chucking,  and  if 
such  bottom  face  is  to  be  shaped  across  its  breadth,  instead 
of  lengthways,  it  is  a  comparatively  slow  operation,  and 
much  time  will  be  saved  by  so  marking  off  the  bar  that 
the  bottom  will  only  just  true  up,  so  that  all  the  surplus 
metal  will  be  cut  off  the  top  face,  which,  being  done  in  a 
larger  machine,  and  lengthways,  is  a  much  more  rapid 
operation.  There  is,  however,  a  method  of  obtaining  both 
the  advantage  of  taking  as  little  as  possible  off  the  top 
face,  and  planing  the  bottom  face  for  the  most  part  length- 
ways. It  is  shown  in  Fig.  307,  A  being  the  bar ;  the  two 


faces,  B  B,  may  be  first  planed  parallel  (as  required)  with 
the  face,  C ;  the  back  of  the  bar  may  then  be  planed 
in  two  operations  from  the  point,  D,  to  the  junction  with 
B  at  each  end.  Were  this  method  of  procedure  employed, 
it  would  pay  to  leave  the  most  metal  to  come  off  the  hack 
of  the  bar ;  but  there  are  yet  other  considerations,  which 
are  the  facilities  in  the  shop.  If  the  shaping  machines 
are  not  kept  fully  occupied,  while  the  planing  machines 


LINING   OR  MARKING  OUT  WORK.  375 

are  always  in  demand,  it  will  pay  (if  there  are  not  many 
bars  to  be  planed)  to  leave  as  little  as  needs  be  to  be  taken 
off  the  bottom  of  the  bar  and  the  remainder  off  the  top. 
If,  however,  many  bars  are  to  be  planed,  the  most  econom- 
ical of  all  methods  will  be  to  plane  the  backs  by  placing, 
say  8  of  them  at  a  time  across  the  table  of  the  planer, 
cutting  off  the  ends  at  the  same  chucking.  Supposing 
this  plan  to  be  adopted,  we  set  the  scriber  of  the  marking 
block  just  below  the  lowest  part  of  the  surface  of  the  bar, 
and  draw  a  line  along  its  planed  surface,  and  then  another 
line  along  each  end,  to  denote  the  thickness  of  the  parallel 
parts  at  each  end,  making  this  line  longer  than  is  neces- 
sary, as  a  guide  in  setting  the  bar  in  the  shaper  (in  case 
the  ends  are  shaped  and  not  planed).  We  next  mark  oft* 
the  length  of  the  bar  at  the  ends,  using  a  square  and  al- 
lowing about  an  equal  amount  to  be  taken  off  each  end  ; 
and  then,  still  using  the  square,  we  mark  a  line  equidis- 
tant between  the  end  lines  to  denote  the  centre  of  the 
length  of  the  bar,  which  will  then  present  the  appearance 
shown  in  Fig.  308,  the  inside  line,  A  A,  being  for  the  top 

Fig.  308. 


face,  the  lines,  E,  for  the  parallel  ends,  the  lines,  B  B,  for 
the  ends,  and  the  line,  D,  denoting  the  middle  of  the 
length  of  the  bar.  We  now  turn  the  bar  so  that  its 
planed  face  is  uppermost;  and,  setting  a  pair  of  compasses 
to  the  required  thickness  of  the  middle  of  the  bar,  we  set 
one  point  at  the  junction  of  the  lines,  A  and  D,  mark  otf 
with  the  other  point  a  half  circle,  and  then  (turning  the 
bar  over)  adjust  it  upon  the  table,  as  shown  in  Fig.  310, 
A  being  the  table,  and  B  a  block  of  wood  and  wedge  to 
adjust  the  bar,  so  that,  if  the  scribing  block  be  applied 


37(5 


COMPLETE  PRACTICAL  MACHINIST. 


along  the  table,  the  needle  or  scriber  point  will  mark  just 
fair  with  the  top  of  the  circle  at  D  and  the  mark,  C,  at 
the  end  of  the  taper  part  of  the  bar  (the  mark,  C,  showing 


the  required  distance  from  the  end  of  the  bar).  Having 
made  the  adjustment,  we  draw  the  line,  E,  thus  com- 
pleting the  marking  of  that  half  of  the  bar.  We  next 
remove  the  block  of  wood  and  wedge  to  the  other  end  of 
the  bar,  and  repeat  the  last  operation,  when  the  marking 
of  the  bar  will  be,  so  far  as  its  outline  is  concerned,  com- 
plete. It  will  be  observed  that  we  have  drawn  the  lines 
in  each  case  on  the  one  planed  surface  of  the  bar  only, 
and  not  all  around  the  work.  The  reason  for  this  is  that 
the  planed  face  is  a  guide,  whereby  to  chuck  the  work 
and  ensure  its  being  set  true.  In  the  absence  of  one  true 
face  it  would  be  necessary,  in  marking  off  the  first  face,  to 
mark  the  lines  all  around  the  work,  which,  when  planed 
up,  would  serve  as  a  guide  whereby  to  set  the  work  during 
the  successive  chuckings. 

Fig.  311. 


A 


After  the  faces  and  ends  are  planed  up,  the  holes  in  the 
ends  may  be  marked  by  the  compass  calipers  and  com- 
passes, as  shown  in  Fig.  311,  A  being  the  bar,  and  B  B 


LINING   OR  MARKING   OUT  WORK.  377 

the  compass  calipers  set  to  the  required  distance.  At  the 
junction  of  the  marks  thus  made,  we  make  a  light  centre- 
punch  mark,  and  mark  off  the  circles  for  the  holes,  first 
marking  a  circle  of  the  requisite  size  and  defining  its  out- 
line by  other  light  centrepunch  marks.  We  next  draw 
from  the  same  centre  a  circle  smaller  in  diameter,  and 
define  its  outline  also  by  small  centrepunch  marks;  after 
which  we  take  a  large  centrepunch,  and  make  a  deep  in- 
dentation in  the  centre  of  the  circle,  which  will  appear  as 
shown  in  Fig.  312.  The  philosophy  of  marking  the  holes 
in  this  manner  is  as  follows:  If  the 
Fig.  312.  outside  circle  alone  is  marked, 

there  is  nothing  to  guide  the  eye 
during  the  operation  of  drilling  the 
holes  (in  determining  whether  the 
drill  is  cutting  the  holes  true  to  the 
marks  or  not)  until  the  drill  has 
cut  a  recess  nearly  approaching  the 
size  of  the  circle  marked  ;  if  the  drill  is  not  cutting  true 
to  the  marks,  and  the  drawing  chisel  is  employed,  it  will 
often  happen  that,  after  the  first  operation  of  drawing, 
the  drill  may  not  yet  cut  quite  true  to  the  marks ;  and  it 
having  entered  the  metal  to  its  full  diameter,  there  is  no 
longer  any  guide  to  determine  if  the  hole  is  being  made 
true  to  the  circle  or  not.  By  introducing  the  inside  circle, 
however,  we  are  enabled  to  use  the  drawing  chisel,  and 
therefore  to  adjust  the  position  of  the  hole  during  the  ear- 
lier part  of  the  operation  ;  so  that  the  hole  being  cut  is 
made  nearly  if  not  quite  true  before  the  cutting  ap- 
proaches the  outer  circle,  which  shows  the  full  size  of  the 
hole.  If,  on  nearly  attaining  its  full  diameter,  the  outer 
circle  shows  it  to  be  a  little  out  of  truth,  the  correction  is 
easily  made.  It  is  furthermore  muoh  more  easy  to  draw 
the  drill  when  it  has  only  entered  the  metal  to,  say,  half 
its  diameter  than  when  it  has  entered  to  nearly  its  full 
diameter 

32" 


878 


COMPLETE  PRACTICAL  MACHINIST. 


The  object  of  making  a  large  centrepuuch  mark  in  thn 
centre  is  to  guide  the  centre  of  the  drill,  and  to  enable  the 
operator  to  readily  perceive  if  the  work  is  so  set  that  the 
point  of  the  drill  stands  directly  over  the  centrepunch 
mark.  This  is  of  great  importance  in  holes  of  any  size 
whatever,  but  more  especially  in  those  of  small  diameter, 
say.  for  instance,  4  inch,  because  it  is  impracticable  to  de- 
scribe circles  of  so  small  a  diameter  whereby  to  adjust  the 
drilling;  and  in  these  cases,  if  the  drill  runs  out  at  all, 
there  is  but  little  practical  remedy.  The  centrepunch 
marks  for  such  holes  should  therefore  be  made  quite  deep, 
so  that  the  point  of  the  drill  will  be  well  guided  and 
steadied  from  the  moment  it  comes  into  contact  with  the 
metal,  in  which  case  it  is  not  likely  to  run  to  one  side  at 
sill.  If  a  motion  or  guide  bar  requires  to  have  one  corner 
rounded  off,  as  it  should  have  to  prevent  its  leaving  a 
square  corner  on  the  guide  block,  which  would  weaken 
the  flange  of  the  latter,  the  corner  cannot  be  marked  off, 
but  a  gauge  should  be  made  as  shown  in  Figs.  313  and  314, 


Fig.  314. 


A  in  Fig.  313  being  a  piece  of  sheet-iron,  say  ^  inch 
thick,  with  the  lines,  B  and  C,  and  the  quarter  circle,  D, 
marked  upon  its  surface.  The  metal,  G,  is  then  cut 
away,  and  the  edges  carefully  filed  to  the  lines,  thus  form- 
ing the  gauge,  A,  which  is  shown  upon  the  bar,  F,  in  the 
position  in  which  it  is  applied  when  in  use.  It  is  obvious 
that  such  a  gauge  will  scarcely  suffice  to  get  up  a  very  true 
round  corner;  this,  however,  is  accomplished  by  leaving 


LJNING   OR  MARKING   OUT   WORK. 


379 


the  corner  of  the  work  a  little  full  to  the  gauge  and  then 
filing  it  up  to  the  piece  of  work  fitting  against  it. 

TO   MARK    OFF    THE    DISTANCE    BETWEEN    THE   CENTRES 
OF    TWO   HUBS   OF   UNEQUAL   HEIGHT. 

When  the  heights  of  two  hubs  are  unequal,  as  shown  in 
Fig.  315,  the  distance  required  being  that  from  A  to  B, 
we  must  make  the  necessary  allowance  (in  the  distance  at 

Fig.  315. 


which  we  set  the  compass  or  trammel  points)  for  the  dif- 
ference in  height  of  the  surfaces  upon  which  our  circles 
are  to  be  marked,  from  the  body  of  the  lever  or  arm.  If 

Fig.  316. 


<E 


the  arm  is  to  be  finished  along  its  whole  length,  it  is  better 
to  mark  off  the  body  of  the  arm  first,  which  we  perform 
as  shown  in  Fig.  316.  Setting  our  work  upon  the  table  A, 


380  COMPLETE  PRACTICAL  MACHINIST. 

and  wedging  it  as  shown,  we  mark  off  with  the  scribing 
block  the  lines  CC  and  D  D,  making  their  distance  apart 
the  thickness  of  stem  required,  and  leaving  about  an  equal 
amount  of  metal  to  be  taken  off  each  face.  We  then  mark 
off  the  height  of  each  hub  face,  measuring  from  the  line  C, 
and  scribe  a  line  around  each  hub  face  as  far  as  the  scriber 
point  will  allow.  We  next  mark  off  (with  a  square,  rest- 
ing against  the  surface  of  the  marking-off  table)  the  lines 
E  and  F,  marking  them  as  near  the  centre  of  the  hub  as 
the  eye  will  direct,  their  use  being  simply  as  guides  in 
setting  the  work  in  the  lathe  or  machine.  These  lines 
being  dotted  with  a  fine  centrepunch  to  prevent  their  be- 

Fig.  317. 
1 


E  - 

r  

A 

D 

B               .a. 

c 

A.      ....  

coming  obliterated,  we  next  measure  the  height  of  the  face 
G,  and  that  of  the  face  H,  both  from  the  line  C. 

We  now  turn  to  the  marking-off  table,  and  on  its  surface 
draw  a  straight  line  a  little  longer  than  the  length  of  our 
arm  or  lever,  as  shown  in  Fig.  317,  the  lines  A  A  A  A  rep- 
resenting the  outline  of  the  marking-off  table,  the  line  B  rep- 
resenting the  height  of  the  hub  from  its  surface,  G,  to  the 
line  C,  in  Fig.  317,  and  the  line  B  representing  the  height 
of  the  hub  from  its  surface,  H,  to  the  line  C  in  the  same 
figure.  The  two  lines  B  and  D  are  to  be  struck  at  right 
angles  to  the  line  C,  and  the  distance  between  them  (as 
denoted  by  the  dotted  line  F)  being  the  required  distance 
from  centre  to  centre  of  our  lever.  These  lines  being 


LINING   OR  MARKING   OUT   WORK.  381 

drawn,  we  have  only  to  set  our  compass  or  trammel  pointa 
to  the  length  of  the  dotted  line  E,  to  be  able  to  mark  off 
the  correct  distance  apart  for  the  centres  of  the  circles 
to  be  marked  on  the  faces  of  the  two  hubs.  Proceeding, 
then,  we  place  our  lever  on  the  marking-off  table  in  the 
position  shown  in  Fig.  318;  and  after  putting  a  centre- 

Fig.  318. 


piece  in  each  hole,  we  draw  (along  the  entire  length  of 
the  lever,  and  across  the  faces  of  the  hubs)  the  centre  line 
A,  locating  it  in  the  centre  of  the  stem.  We  then  apply 
the  trammels,  set  as  already  directed,  to  mark  off  the 
centres  of  the  holes.  Setting  our  compasses  at  the  inter- 
section of  the  line  A  with  the  line  marked  on  each  of  the 
hub  faces,  we  strike  the  necessary  circles  on  the  faces  of 
the  hubs,  as  shown.  We  next  mark  off  the  breadth  of  the 
lever  or  arm  on  the  face  from  the  centre  line  A,  and  our 
marking  is  complete. 

MARKING    HOLES    AT   A   RIGHT    ANGLE. 

To  mark  off  a  crosshead  in  which  one  hole  requires  to 
be  at  right  angles  to  the  other,  we  proceed  as  follows: 
First  placing  the  crosshead  upon  the  marking  table,  as  in 
Fig.  319,  we  draw  with  the  scribing  block  the  centre  line 
A,  marking  it  all  round  the  crosshead;  and  if  the  cross- 
head  has  a  hole  or  holes  in  it,  we  put  centre-pieces  in  those 
holes  to  receive  the  centre  lines.  We  then  place  a  square 
with  its  back  resting  upon  the  marking-off  table,  and  draw, 
parallel  with  the  edge  of  the  blade,  the  centre  line  B. 
From  the  intersection  of  the  lines  A  and  B  we  draw  the 


882 


COMPLETE  PRACTICAL  MACHINIST. 


lines  C  and  D,  marking  their  distances  from  the  line  A 
with  a  pair  of  compasses,  and  carrying  the  lines  round 


Fig.  320. 


Fig.  321, 


1 


with  the  scribing  block.   We  draw  the  circle  E  (Fig.  319), 
using  the  line  A  as  a  centre,  and  locating  it,  as  nearly  true 


LINING   OR  MARKING   OUT  WORK.  388 

as  we  cau  (the  other  way),  to  the  hub  or  stem.  We  now 
stand  our  crosshead  in  the  position  shown  in  Figs.  320  and 
321,  and  applying  a  square  to  the  line  A,  we  set  it  to  a 
right  angle  with  the  face  of  the  line  A,  wedging  it  upright 
with  the  wedges  shown.  Then,  setting  the  scribing  block 
needle  point  even  with  the  line  B  of  Fig.  319,  and  setting 
that  line  true  with  the  surface  of  the  table,  we  carry  it 
across  the  other  face,  as  shown  in  Fig.  321,  locating  its 
position  sideways  to  suit  the  forging  or  casting,  and  then 
we  strike  the  circle  F,  which  completes  the  marking. 

It  will  be  noted  that  the  lines  A  and  B  are  mere  guides 
whereby  to  obtain  the  centres  of  the  circles  from,  and  it 
may  therefore  be  asked  for  what  .purpose  those  lines  are 
centrepunch-marked.  The  reply  is,  that  those  lines  must 
be  used  as  guides  to  set  the  work  by  when  chucking  the 
crosshead  on  the  lathe  or  machine. 

TO    LINE   OUT   A    DOUBLE    EYE. 

After  measuring  the  dimensions  of  a  double  eye  to  as- 
certain if  there  is,  upon  the  outline,  surplus  metal  sufficient 
to  permit  of  its  clearing  up  all  over,  we  apply  an  L  square 
upon  the  outside  surfaces,  and  a  T  square,  with  the  blade 
between  the  jaws,  to  test  if  the  inside  and  outside  faces 
are  at  about  a  right  angle  to  each  other,  or  if  the  marking 
will  have  to  be  thrown  to  one  side  of  the  work  to  accom- 
modate a  want  of  truth  in  the  latter.  Presuming  that,  as 
is  usually  the  case,  the  work  is  reasonably  near  to  being 
true,  we  proceed  as  follows :  Placing  the  double  eye  upon 
the  marking-off  table,  as  shown  in  Fig.  322,  we  block  up 
the  stem  end  with  the  pieces  of  wood,  B,  so  that  the  hori- 
zontal faces  of  the  work  will  stand  about  true  with  the  sur- 
face of  the  table,  the  manner  of  testing  the  same  being 
shown  as  applied  to  a  square  block  in  Fig.  323,  A  repre- 
senting the  marking-off  table,  and  B  the  scribing  block, 
with  the  needle  placed  on  a  piece  of  work  so  that  the  point 
of  the  bent  end  barely  touches  the  surface  of  the  work.  The 


384 


COMPLETE  PRACTICAL  MACHINIST: 


operation  is  to  move  the  scribing  block  from  end  to  end 
of  the  work  and  on  both  sides  of  it,  packing  it  up  until 
the  upper  surface  is  level,  and  hiking  care,  if  the  work 

Fig.  322. 


Fig.  323. 


does  not  lie  level  and  steady  upon  the  table,  to  insert 
wedges  in  the  necessary  places  so  that  the  work  will  lie 
firmly  and  not  move  during  the  operation  of  marking. 


LINING   OR  MARKING   OUT  WORK.  385 

If  there  are  projections  upon  the  face  of  the  work  which 
rests  upon  the  table,  as  is  the  case  in  our  double  eye,  it  is 
necessary  to  pass  the  scribing  block  along  the  under  as 
well  as  the  upper  surface  of  the  work  ;  and  if  the  two 
vary  much,  we  may  choose  the  one  that  is  most  true  with 
the  other  surfaces  of  the  work  and  set  it  true ;  or  if,  in 
such  case,  there  would  not  be  enough  metal  to  clean  up 
the  work  on  both  sides,  we  must  divide  the  difference  be- 
tween the  two.     We  then  put  between  the  jaws  of  the 
double  eye,  the  centre  piece,  C,  Fig.  322,  and  find  the 
centre  of  the  jaws,  as  shown  by  D;  then,  setting  a  pair  of 
compasses  to  half  the  required  width  between  the  jaws, 
we  scribe  upon  both  the  jaws  the  segments  of  a  circle,  E 
and  F,  using  D  as  a  centre ;  then  opening  the  compasses 
to  allow  for  the  requisite  thickness  of  each  jaw,  we  mark 
the  segments  of  a  circle,  G  and  H ;  and  again  setting  the 
compasses  to  the  requisite  thickness  of  hub,  we  mark  the 
segments  of  a  circle,  I  and  J.     We  now  take  a  scribing 
block,  and,  setting  the  point  just  to  intersect  the  extreme 
diameter  in  each  case,  we  draw  the  lines,  K  and  L,  M  and 
N,  and  O  and  P,  thus  defining  the  widths  and  thicknesses 
of  the  jaws  and  hubs.     We  then  set  the  scriber  point  even 
with  the  centre,  D,  and  then  draw  the  line,  S  S,  which 
should  run  a  long  way  up  the  stem  of  the  double  eye,  be- 
cause the  shortness  of  the  other  lines,  running  parallel  to 
it,  renders  it  difficult  to  set  the  work  true  by  them,  and 
S  S  is  made  long  to  supply  the  deficiency.     After  setting 
the  compasses  to  half  the  required  thickness  of  the  stem, 
we  mark,  using  the  line,  S  S,  as  a  centre,  the  segments  of 
a  circle,  Q,  and  R,  and  from  them  mark  the  lines,  T  and 
U,  which  define  the  required  thickness  of  the  stem  or  rod 
of  the  double  eye.     Our  next  operation  will  be  to  mark 
off  the  hole  and   the  circle  of  the  hub,  which  is  done  as 
shown  in  Figs.  324  and  325.     Setting  the  eye  upon  the 
marking-off  table,  A,  we  wedge  it  upright,  as  shown  in 
the  side  view,  Fig.  324.  by  the  wedges,  B ;  applying  the 
33 


386 


COMPLETE  PRACTICAL  MACHINIST. 


blade  of  an  L  square  to  set  the  line,  S  S,  Fig.  325,  true 
by,  we  mark  off  on  each  side  of  the  double  eye  the  centre 


Fig.  324, 


Fig.  325. 


Fig.  326. 


of  the  boss  or  eye,  and  from  that  mark  off  the  circles,  Y 
and  W,  denoting  the  finished  sizes  of  the  hole  and  the 


LINING  OR  MARKING   OUT   WORK.  387 

eye;  then  setting  the  scribing  block  needle  point  even 
with  the  centre  from  which  the  circles,  V  and  W,  were 
struck,  we  mark  on  the  centre  piece  (shown  in  Fig.  325), 
the  line,  X. 

We  have  now  co  complete  the  marking-off  of  the  edge 
face  shown  in  view  2,  Fig.  325,  which  could  not  have  been 
done  before,  because  there  was  nothing  determinate  where- 
frorn  to  mark  off  the  half  circle  of  the  outline  between 
the  jaws.  Placing  the  double  eye  upon  the  table,  as 
shown  in  Fig.  326,  and  blocking  it  up  so  that  it  lies  level 
with  the  face  of  the  marking-off  table,  and  with  the  face 
that  has  been  marked  off,  uppermost,  we  insert  between 
the  jaws  the  centre  piece,  B.  We  next  mark  from  the 
centre,  C,  the  requisite  distance  from  the  hole  in  the  eye 
to  the  crown  of  the  curve,  between  the  jaws,  thus  ob- 
taining the  centre  mark,  D,  from  the  centre,  C;  and  set- 
ting the  compasses  to  half  the  required  width  between  the 
jaws,  we  use  D  as  a  centre,  and  mark  upon  the  centre 
piece,  B,  the  centre,  E,  and  then  strike  the  half  circle, 
F  F,  which  completes  the  marking  between  the  jaws. 
Our  next  procedure  is  to  mark  off  the  segments  of  circles, 
G,  G,  which  are  struck  from  the  centres,  H,  H,  respect- 
ively. Then  taking  the  block  of  wood,  I,  which  should 
stand  at  about  the  same  height  from  the  marking-off  table 
as  does  the  body  of  the  double  eye,  and  setting  the  compass 
to  the  required  radius,  we  rest  one  point  on  the  circle,  G, 
at  about  the  point,  J,  we  strike  the  mark,  K  ;  then  placing 
one  leg  of  the  compasses  at  about  the  point,  L,  we  strike 
the  line,  M,  the  junction  of  the  lines,  K  and  M,  forming 
the  location  of  the  centre  from  which  the  segment  of  a 
circle,  N,  is  marked.  Placing  the  block  of  wood,  I,  on 
the  other  side  of  the  double  eye,  we  repeat  this  latter 
operation,  and  the  marking  on  that  face  is  complete. 

After  defining  the  outline  of  our  work  by  light  centre 
punch  marks,  we  pass  it  to  the  machinist's  hands  to  be 
turned  and  cut  down  to  the  lines,  after  which  we  place  it 


COMPLETE  PRACTICAL  MACHINIST. 


upon  the  marking-off  table  in  the  position  shown  in  Fig. 
327,  A  representing  the  table.  At  each  side  of  the  double 
eye  we  place  in  the  hole  a  centre  piece,  B,  and  mark 

Fig.  327. 


D 


thereon  the  centre  of  the  hole  with  the  compass  calipers. 
We  then  find  the  centre  of  the  shank,  C,  and,  wedging 
that  end  up  with  wood  as  shown,  we  set  the  needle  of  the 
scribing  block  even  with  the  centre  of  the  hole,  and  so 
adjust  the  double  eye  with  wedges  that  the  needle  point 
will  strike  the  centre  of  the  hole  marked  on  B,  on  each 
side,  and  also  the  centre,  C,  whereupon  we  may  mark  the 
line,  D;  then  setting  the  compasses  to  the  requisite  dis- 
tance, we  mark  from  the  centre,  C,  the  segments  of  circles, 
E  and  F,  and  resetting  the  compasses  on  account  of  the 
taper  from  the  centre,  G,  the  seg- 
ments of  circles,  H  and  I:  and  re- 
setting the  double  eye  so  that  the 
needle  point  of  the  scribing  block 
will  intersect  the  extreme  outline 
of  K  and  E,  we  draw  the  line,  J; 
repeating  the  operation  on  the 
under  side,  we  produce  the  line, 
K,  and  the  operation  is  complete. 
The  curves,  L  L,  are  made  to  a 
such  as  is  shown  in  Fig. 


Fig.  328. 


o' 


B 
O 


gauge,  sucn  as  is  snown  in 
328 ;  it  is  made  of  sheet-iron  about  one-sixteenth  o/  an  inch 
thick,  the  outline  being  carefully  marked  out  and  filed  up 
neatly,  the  corner,  A,  being  made  of  the  necessary  sweep, 
and  the  hole,  B.  being  used  to  hung  the  gauge  up  by.  It 
33  "<• 


LINING   OR  MARKING   OUT   WORK.  3S9 

is  well  to  have  an  assortment  of  such  gauges  for  use  in 
lining  out,  as  well  as  for  use  as  guides  to  the  machinist  m 
cutting  out  the  curves  or  sweeps. 

To  assist  the  operator  in  marking  out,  the  centres  from 
which  all  curves  and  circles  on  detail  drawings  are  struck 
should  have  a  small  circle  in  red  ink  marked  around 
them,  and  a  dotted  red  line  marked  from  the  centre  to 
the  circle  or  segment  of  circle  struck  from  it,  similar  to 
the  dotted  straight  lines  shown  in  Fig.  326.  If  the 
double  eye  is,  however,  intended  to  have  an  offset,  as 

Fig.  329. 


shown  in  Fig.  329,  we  draw  from  the  centres,  C  and  D, 
the  line,  A ;  and  setting  the  compasses  to  the  amount  of 
the  offset,  we  draw  the  segment  of  a  circle,  E,  using  the 
line,  A,  as  a  centre;  and  from  the  extremity  of  that  seg- 
ment, we  draw  with  the  scribing  block  the  line,  B,  which 
will  represent  the  centre  line  of  the  stem  of  the  double 
eye,  the  rest  of  the  operation  being  as  shown  in  Fig.  322. 
and  described  in  the  accompanying  explanation,  from  the 
point  at  which  the  line,  S  S,  in  that  figure  was  drawn. 

MARKING    OUT    AN    ECCENTRIC. 

In  measuring  an  eccentric  to  ascertain  if  it  has  sufficient 
stock  to  allow  it  to  be  cleaned  up  all  over,  it  is  not  suf- 
ficient to  measure  the  thickness,  the  outside  diameter,  and 


390 


COMPLETE  PRACTICAL  MACHINIST. 


the  size  of  the  bore  only,  because  those  measurements  do 
not  take  the  amount  of  the  throw  into  consideration,  and 
we  have,  therefore,  to  proceed  as  follows: 

In  Fig.  330  let  A  A  re- 
present an  eccentric,  into 
the  bore  of  which,  on  the 
hub  side,  we  place  the  cen- 
tre piece,  and  mark  upon  it 
the  centre  of  the  hole.  We 
then  take  a  pair  of  com- 
passes, and  set  them  so 
that,  when  one  point  is  rest- 
ing in  the  centre  of  the 
hole,  the  other  point  will 
reach  to  within  about  a 
quarter  of  an  inch  of  the 
extreme  diameter  of  the  ec- 
centric, as  shown  above  by  the  line,  C  C.  We  then,  with 
a  pair  of  compass  calipers,  find  the  centre  of  the  line, 
C  C,  by  resting  the  caliper  leg  of  the  same  against  the 
periphery  of  the  eccentric,  at  one  of  the  points  where  the 
line,  C  C,  meets  it;  and  then  with  the  compass  leg  of  the 
compass  calipers,  we  mark  the  line,  E;  and  repeating  the 
operation  at  the  other  end  of  the  line,  C  C,  we  mark  the  line, 
F.  We  next  take  a  straight  edge;  and  placing  it  so  that 
its  edge  is  even  with  the  centre  of  the  bore  of  the  eccentric 
and  with  the  centre  between  the  lines,  E  and  F,  we  draw 
the  line,  G  g,  upon  which  we  may  make  our  measurements 
as  follows:  After  setting  a  pair  of  compasses  to  the  amount 
of  throw  required  by  the  eccentric,  we  place  one  compass 
leg  in  the  centre  of  the  bore,  and  with  the  other  mark  (on 
the  line,  G)  the  line,  K,  which  will  represent,  at  its  inter- 
section with  G,  the  centre  of  the  finished  diameter  of  the 
eccentric.  Then  we  take  a  rule,  and  measure  from  the 
centre,  K,  to  the  ends,  H  g,  of  the  line,  G,  which  ends 
should  be  equidistant  from  K,  if  the  amount  to  come  off 


LINING   OR  NARKING    OUT  WORK.  391 

the  surface  of  the  castiDg  in  the  hole  is  to  equal  that  to 
come  off  the  outside  surface.  It  very  frequently  happens, 
however,  that  there  will  be  more  to  come  off  the  eccentric 
on  one  side  of  the  diameter  than  on  the  other,  especially 
when  the  eccentric  is  put  together  in  two  halves;  because, 
in  facing  up  the  two  halves,  preparatory  to  putting  them 
together,  and  to  make  them  bed  well  one  to  the  other,  it 
does  not  always  happen  that  the  same  amount  of  metal  is 
taken  off  each  face.  Again,  the  quantity  so  taken  off  is 
not  always  that  allowed  on  the  pattern  for  the  purpose; 
so  that,  in  practice,  an  eccentric  casting  rarely  marks  off 
true  with  its  rough  outline. 

Here,  then,  arises  the  consideration  as  to  in  what  direc- 
tion we  shall  throw  the  lines.  Shall  it  be  to  bore  the  hole 
true,  or  to  turn  the  outside  diameter  true,  with  the  cast- 
ing? The  latter  plan  is  always  preferable ;  because,  if  in 
turning  up  the  outside  diameter  the  first  cut  does  not  true 
it  up,  the  tool  point  will  scrape  over  the  sand,  after  leav- 
ing the  cut  and  before  it  strikes  it  again,  to  such  an  extent 
as  to  rapidly  destroy  the  cutting  edge,  necessitating  not 
only  frequent  regrinding  of  the  tool,  but  also  that  its  cut- 
ting speed  be  very  materially  reduced.  After  having 
roughly  ascertained,  in  the  manner  described  (which  pro- 
cess will  take  but  a  few  minutes  to  perform),  that  there  is 
surplus  metal  enough  to  clean  up  the  eccentric,  we  may 
proceed  to  mark  it  out. 

It  is  much  easier  to  mark  off  an  eccentric  on  its  plain 
side  than  on  the  side  on  which  the  hub  stands,  because 
of  the  projection  of  the  hub;  and,  furthermore,  the 
marking  for  the  hole  and  for  the  diameter  can  be  per- 
formed at  one  operation,  which  is  impracticable  on  the 
hub  side.  But  if  this  plan  is  not  adopted,  it  necessitates 
that,  at  the  first  chucking,  either  the  hole  only  shall  be 
bored,  in  which  case  there  will  be  no  face  true  with  the 
hole,  and  hence  no  guide  whereby  to  set  the  eccentric  at 
the  next  chucking:  or  else,  in  turning  off  the  outside 


COMPLETE  PRACTICAL   MACHINIST. 


Fig.  331. 


after  the  hole  is  bored,  the  marks  for  the  second  chucking 
will  be  effaced.  The  main  consideration,  however,  is  that 
there  is  only  one  way  to  chuck  an  eccentric  to  insure  its 
being  turned  as  true  as  possible;  and  the  marking  off 
must,  therefore,  be  made  to  accommodate  the  chucking, 
the  method  and  reasons  for  which  are  explained  in  the 
remarks  on  eccentrics,  on  page  136. 

The  lines  to  mark  the  location  of  the  hole  and  the 
thickness  of  the  hub  may  be  marked  in  the  manner  shown 
in  Fig.  330  or  we  may  adopt  the  plan  shown  in  Fig.  331, 
which  is  perhaps  the  better  of  the  two. 

From  the  four  points 
A,  B,  C,  and  D,  we 
mark  off,  on  the  hub 
side  of  the  eccentric,  the 
centre  of  its  diameter, 
E;  we  then,  setting  a 
pair  of  compasses  to  the 
amount  of  throw  re- 
quired for  the  eccentric, 
mark  off  from  the  centre, 
E,  the  arc,  F;  then, 
with  a  pair  of  compass 
calipers,  placed  in  each 
case  with  oneend  against 
the  bore  of  the  casting, 

we  mark  the  arcs,  G  and  H,  the  junction  of  the  arcs,  F, 
G,  and  H,  being  the  required  centre  of  the  hole.  We 
therefore  strike  from  that  centre,  around  the  face  of  the 
hub,  the  line,  I,  and  mark  it  lightly  with  a  centrepunch, 
as  shown.  If,  however,  it  should  be  found  that  there  is 
not  sufficient  metal  to  allow  the  hole  to  be  cleaned  up  if 
marked  off  true  with  the  circumference,  we  must  throw  the 
hole  a  little  in  the  requisite  direction,  endeavoring  (for 
the  reasons  already  stated)  to  keep  the  diameter  of  the 
eccentric  as  nearly  true  for  the  throw  as  possible.  For 


LTNTNG    OR  MARKING    OUT   WORK. 


393 


Fig.  332. 


instance,  in  Fig.  332,  if  we  suppose  there  is  an  insufficiency 
of  metal  in  the  hole,  at  A  (E  being  the  centre  of  the 
diameter  of  the  eccentric,  and  K  the  amount  of  the 
throw),  we  first  set  a  pair  of  compasses  to  the  required 
radius  of  the  diameter;  and  from  the  centre,  E,  strike 
the  circle,  F,  which  will  show  the  amount  of  metal  re- 
<pired  to  be  taken  off  the  circumference  of  the  work,  and 
therefore  to  what  degree  we  are  able  to  throw  the  hole  to 
accommodate  the  scant  spot,  A.  If  there  is  more  metal 
between  the  line,  F,  and  the  periphery  than  the  spot,  A. 
kcks,  the  eccentric  will  clean  up,  and  we  may  mark  off 
the  hole,  allowing  it  to  just  clean  up,  as  shown  by  the 

circle,  L.  It  is,  however, 
best,  on  small  eccentrics,  to 
mark  the  circle,  L,  as  large 
as  the  face  on  which  it  is 
marked  will  admit;  be- 
cause, the  larger  the  circle, 
the  less  a  slight  want  of 
truth  in  the  chucking  will 
affect  the  truth  of  the 
work.  It  will  be  observed 
that,  in  consequence  of  the 
centrepiece  standing  above 
the  level  of  the  face  (to 

the  amount  of  the  height  of  the  hub),  the  circle,  F,  in 
Fig.  831,  would  be  too  small  if  marked  with  the  compasses 
set  to  the  correct  radius ;  but  since  the  duty  of  that  circle 
is  to  merely  indicate  the  amount  of  surplus  metal  on  the 
outside  diameter,  it  will  be  sufficiently  correct  on  ordinary 
eccentrics,  to  mark  it  as  directed,  making  a  slight  allow- 
ance of  increase  in  setting  the  compasses  to  draw  that 
circle.  If,  however,  it  should  happen  that  the  quantity 
of  stock  is  so  scant  as  to  make  it  questionable  whether 
the  work  will  true  up :  then  the  centre  piece  may  be 
lowered  in  the  hole  to  the  level  of  the  surface  of  the  metal 


COMPLETE  PRACTICAL  MACHINIST. 


Fig.  333. 


on  which  the  circle,  L,  is  marked,  and  the  compasses  may 
be  set  to  the  correct  radius. 

The  hole  being  marked,  no  further  marking  should  be 
performed  until  the  eccentric  has  had  both  sides  finished 
and  the  hole  bored,  when  the  diameter  should  be  marked 
upon  the  plain  side  of  the  work,  as  shown  in  Fig.  333, 
After  inserting  the  centre  piece,  and  marking  off"  upon  it 
the  exact  centre  of  the  hole,  we  mark  the  line,  C  C ;  and 
finding  the  centre  of  its  length,  as  already  described,  we 
strike  the  line,  D;  then  we  mark  on  the  line,  D,  the 
amount  of  the  throw,  measuring  from  the  centre  of  the 
hole,  and  we  thus  obtain 
the  centre,  F,  from  which 
we  mark  the  circle,  G  G, 
which  is  only  intended  to 
be  employed  in  setting 
the  work,  and  need  not, 
therefore,  be  made  of  any 
particular  size.  The 
marking  will  thus  be 
completed,  and  it  will  be 
noted  that  the  thickness 
of  the  eccentric  and  the 
hub,  and  the  height  of 
the  latter,  have  not  been 
dealt  with  at  all,  the  reason  for  the  omission  being  that 
it  is  entirely  unnecessary  to  regard  them,  since  (providing 
of  course  that  there  is  spare  metal  enough  to  clean  them 
up)  they  may  safely  be  left  to  the  turner,  who  may  ac- 
commodate the  amount  taken  off  the  first  side  faced,  ac- 
cording to  the  smoothness  of  the  second  cut,  or  a  variety 
of  other  conditions  which  need  not  be  here  enumerated. 
If  the  eccentric  has  no  hub,  as  is  sometimes  the  case,  it 
should  be  marked  off,  as  shown  in  Fig.  331. 

After  the  turning  is  completed,  the  key  way  or  feather- 
w  ;  may  be  marked  off,  as  shown  in  Fig.  334.     Placing 


LINING   OR  MARKING   OUT  WORK. 


395 


Fig.  334. 


the  centre  piece  on  the  hub  side  of  the  eccentric,  so  that 

the  plain  side  may  lie  flat  on  the  slotting  machine  table, 

and  not  require  parallel  strips  or  packing  wherewith  to 

chuck  it,  we  mark  off 
upon  it  the  centre  of  the 
hole  in  the  eccentric;  and 
from  that  centre,  we 
mark  a  circle  whose 
diameter  must  be  equal 
to  the  required  width  of 
the  key  way  to  be  cut. 
Then  selecting  the  loca- 
tion of  the  key  way,  we 
describe  there  another 
circle  of  the  same  diani" 
cter  as  at  A.  Placing  a 
straight  edge  so  that  one 

of  its  edges  is  just  even  with  one  and  the  same  side  of  each 

circle,  we  draw  the  line,  A ;  and  by  repeating  the  opera- 
tion on  the  other  side  of 

the  circle,  we  shall  have 

the  sides  of  the  key  way 

marked.      To   mark   the 

depth,   we   make   a   fine 

ceutrepunch  mark  at  the 

requisite    distance    from 

the  bore  of  the  eccentric, 

and  then,  using  a  square 

place    one   of    its   edges 

parallel    with    the   outer 

edges  of  the  two  circles, 

and   the  other   edge  fair 

with   the   centre   of  the 

centrepunch  mark,  and  scribe  a  line  along  the  latter  edge 

and  across  the  width  of  the  keyway,  the  operation  being 

shown  in  Fig.  335,  A  being  the  square.     When,  however, 


Fig.  335. 


396 


COMPLETE  PRACTICAL  MACHINIST. 


there  are  a  number  of  keyways  of  the  same  width  and 
depth  to  be  marked,  it  is  more  expeditious  to  make  the 
gauge  shown  (together  with  its  method  of  application)  in 
Fig.  336,  in  which  A  represents  the  gauge,  being  a  piece  of 
sheet-iron  about  one-sixteenth  of  an  inch  thick,  the  curved 
line  being  of  the  same  curvature  as  the  bore  of  the  hole 
in  the  eccentric,  and  the  projection,  B,  being  of  the  re- 
quired size  of  key  way.  The  ends,  C  D,  are  to  be  slightly 
bent  (both  in  one  direction),  so  that,  while  the  projection, 
B,  will  lie  on  the  face  of  the  hub,  the  ends,  C  D  (being 
depressed),  will  contact  with  the  bore  of  the  hole  of  the 

Fig.  336. 


eccentric  and  thus  serve  to  keep  the  gauge  true  with  the 
bore.  The  gauge  should  be  carefully  marked  out  and 
smoothly  filed  true  to  the  lines.  The  small  hole,  shown 
near  C,  is  to  hang  up  the  gauge  by  when  it  is  not  in  use. 

LINING   OUT   CONNECTING    RODS. 

Connecting  rods,  so  large  in  size  as  to  be  cumbrous  to 
handle,  are  generally  made  by  forging  the  ends  to  which 
the  strap  is  attached  by  themselves,  and  afterwards  weld- 
ing them  to  the  body  of  the  rod :  the  advantage  being 
that  the  machine  work  done  to  the  rod  ends  can,  in  that 
case,  be  done  in  small  machines  and  at  a  higher  rate  of 


LINING   OR  MARKING    OUT  WORK.  897 

cutting  speed  than  would  be  possible  if,  the  rod  being 
solid,  its  whole  body  had  to  be  chucked  in  order  to  ope- 
rate on  the  ends  only.  If  any  finishing  is  required  to  the 
body  of  the  rod,  it  is  in  such  case  done  after  the  rod  ends 
are  welded  to  it  and  made  true  to  the  already  finished 
block  end  of  the  rod.  If,  however,  the  rod  is  forged  solid, 
the  whole  of  the  marking-off  should  be  gauged  to  suit  the 
body  of  the  rod.  For  instance :  If  the  stem  of  the  rod  is 
round,  the  marking-off  of  the  ends  should  be  performed 
from  a  centre  marked  off  true  with  the  round  stem  and 
on  the  end  face  of  the  rod.  The  first  operation  should  in 
this  case  be,  after  marking  off  the  said  centre,  to  put  the 
rod  in  the  lathe  and  face  off  the  block  end  faces,  thus  giving 
us  a  face,  at  each  end  of  the  rod,  true  with  the 
l$'  '  stem  of  the  rod,  and  therefore  useful  not  only 
to  receive  the  marking  off  lines  but  also  as  a 
face  whereby  to  true  the  other  faces  on  the 
block  or  stub  end.  If  tlie  ends'are  forged  sepa- 
rately from  the  body  of  the  rod,  it  is  better  to 
face  off  one  of  the  side  faces,  and  to  mark  off 
on  that  side  face.  To  mark  off  a  rod  end  that 
is  forged  solid  with  the  stem  of  the  rod,  we 
proceed  as  shown  in  Fig.  337,  A  representing 
the  centre,  true  with  the  body  of  the  rod ;  B  B  shows  the 
diameter  of  the  rod  end  struck  with  the  compasses  from 
the  centre,  A,  and  C  C,  the  thickness  of  the  rod  struck  in 
like  manner.  If  there  should  not  be  sufficient  metal  on 
the  block  end  to  permit  the  marking-off  to  be  performed 
from  the  centre,  A,  when  true  with  the  body  of  the  rod, 
that  centre  must  be  moved  sufficiently  to  allow  the  rod 
end  to  be  cleaned  up ;  this  is,  however,  to  be  avoided  if 
possible,  for  the  following  reasons:  If  the  body  of  the  rod 
runs  much  out  of  true,  the  turning  of  it  in  the  lathe  will 
be  a  slow  process,  because  such  rods  are  liable,  from  their 
length,  to  spring  in  consequence  of  the  pressure  of  the 
cut.  Hence  it  is  not  practicable  to  take  heavy  cuts  along 
34 


398  COMPLETE  PRACTICAL  MACHINIST. 

it;  and  if  in  consequence  of  the  body  of  the  rod  running 
much  out  of  true,  it  cannot  be  cleaned  up  at  one  cut,  the 
tool  will  scrape,  during  the  first  cut,  against  the  scale, 
necessitating  that  the  cutting  speed  of  the  tool  be  much 
less  than  it  otherwise  need  be. 

After  the  segment  of  circles,  B  B  and  C  C,  in  Fig.  337, 
are  struck,  which  may  be  done  before  setting  the  rod  on 
the  markiug-off  table,  the  rod  should  be  set  on  the  mark- 
ing-off  table  with  one  of  the  broad  faces  downwards,  and 
with  the  scribing  block  needle  point  placed  level  with  the 
mark,  C,  on  the  upper  face;  and  the  rod  should  be  tried 
along  that  face  to  ascertain  if  there  is  sufficient  metal  to 
clean  it  up  all  across.  The  scribing  block  should  then  be 
carried  to  the  other  end  of  the  rod,  and  tried  with  the 
upper  n.ark,  C;  and  that  being  found  correct,  the  scriber 
point  should  be  set  to  the  lower  mark,  C,  at  each  end  of 
the  rod;  and  thus  the  two  lines  across  the  rod  end,  repre- 
senting the  thickness  thereof,  may  be  drawn  by  the  scrib- 
ing block  at  each  end  of  the  rod.  The  lines  representing 
the  breadth  of  the  block  end  of  the  rod  may  then  be 
drawn  by  simply  placing  a  square  on  the  surface  table, 
with  the  edge  of  the  square  placed  in  each  case  level  with 
the  extreme  diameter  of  the  segments  of  circles,  B  B, 
Fig.  337.  No  other  lines  in  this  case  will  be  required, 
because  the  rod  ends,  having  been  turned  in  the  lathe,  give 
the  machinist  two  true  faces  whereby  to  set  the  rod  at  each 
chucking.  If  the  rod  ends  are  not  welded  to  the  rod,  the 
better  plan  is  to  have  one  of  the  broad  surfaces  on  each 
rod  end  surfaced  up  in  a  planing  machine,  and  to  then 
perform  the  marking  out  on  the  surfaced  faces.  The 
marking  out  should  be  made  about  true  with  the  stem  of 
the  rod,  as  shown  in  Fig.  338.  The  surfaced  face  is  to  be 
set,  by  a  square,  to  a  right  angle  to  the  marking-off  table 
face;  and  the  centre  line,  A  A,  of  the  stem  is  found  from 
the  body  of  the  stem,  and  carried  from  end  to  end  of  the 
forging  as  a  guide  to  set  the  work  by,  the  lines,  B  B  or 


LINTSQ   OR  MASKING   OUT  WORK. 


309 


0  C,  being  too  short  to  serve  the  purpose.  These  latter 
lines  are  struck  equidistant  from  A  A.  The  line,  D, 
should  be  struck  with  a  square  resting  on  the  marking 
table,  and  any  surplus  metal  should  be  taken  off  the  end 
face  rather  than  out  of  the  corner  where  the  butt  joins 
the  stem;  because  it  is  easier  to  take  the  metal  off  the  end 
than  out  of  the  shoulder.  The  round  corners  need  not  be 
marked,  it  being  preferable  to  make  a  gauge  to  shape 
them  to.  The  edges  thus  marked  being  shaped  off,  the 
thickness  of  the  butt  end  may  be  marked  off  by  a  scrib- 
ing block,  the  planed  surface  of  the  butt  end  lying  flat  oil 
the  marking  table.  The  strap  should  first  have  one  face 

Fig.  338. 


surfaced,  and  then  a  centre-piece  should  be  placed  between 
the  jaws,  being  made  just  sufficiently  tight  to  be  held,  and 
not  so  tightly  as  to  sensibly  spring  the  jaws  open;  otherwise, 
while  the  thickness  of  the  jaws  would  be  marked  off  cor- 
rectly, the  width  between  them  and  their  outside  diameter 
would  be  too  small  when  finished.  The  strap  should  then 
be  placed  on  the  marking  table,  and  marked  as  shown  in 
Fig.  339,  the  lines  A  A,  B  B,  and  C  C,  being  marked  off 
to  the  required  widths  apart  and  equidistant  from  the 
centre  line,  marked  across  the  centre-piece  and  across  the 
crown  of  tho  strap,  at  D  E.  The  centre  of  the  centre- 
piece having  beeu  obtained  from  the  inside  of  the  jaws, 


400  COMPLETE  PRACTICAL  MACHINIST. 

and  carried  across,  at  D  E,  after  the  strap  is  set  upon  the 
table  with  the  inside  faces  of  the  jaws  parallel  with  the 
face  of  the  table,  the  width  between  the  lines,  A  A,  should 
be  marked  less  than  is  the  width  of  the  block  end  on 
which  they  fit,  for  the  following  reasons:  A  connecting 
rod  strap  will,  by  reason  of  its  shape,  spring  open  between 
its  jaws  very  easily  indeed ;  and  were  the  width  between 
the  jaws  made  the  same  as  that  of  the  block  end  of  the 
rod,  the  strap  would  fit  very  loosely  to  -its  place.  It  is 
therefore  necessary  to  make  allowance  for  this  in  the 
width  between  the  jaws  of  the  strap,  making  them  nar- 
rower than  the  block  end  of  the  rod.  The  amount  of  this 
allowance  depends  upon  the  size  and  stoutness  of  the  strap, 
an  ordinary  proportion  being  about  one-sixteenth  of  an 
inch  to  a  strap  eight  inches  wide  between  the  jaws.  This 
amount  of  allowance  will  enable  the  strap  to  spring  over 
the  rod  end,  and  be  a  good  fit;  that  is  to  say,  not  so  tight 
but  that  it  can  be  easily  pulled  off  by  the  hand,  and  not 
so  loose  as  to  fall  off  of  its  own  weight  if  unsupported. 
Then,  again,  any  ordinary  amount  of  metal  removed  in 
fitting  the  strap  to  the  rod  end  will  not  seriously  affect 
their  fit  together.  Now  it  is  obvious  that,  if  the  rod  end 
faces  on  which  the  jaws  of  the  strap  fit  are  made  parallel 
to  each  other,  the  strap,  in  being  sprung  on,  would  spring 
open  so  that  its  jaws  would  only  touch  the  block  at  its 
entrance  end,  the  end  of  the  jaws  standing  Open  from  the 
block  end.  To  obviate  this,  the  block  end  faces  B  B,  in 
Fig.  338,  are  made  slightly  taper,  that  is  to  say,  about 
one-thirty-second  of  an  inch  or  rather  less  in  a  length  of 
six  inches,  the  diameter  of  the  end  being  the  smaller.  It 
is  not  necessary  to  mark  so  small  an  amount  of  taper  in 
the  marking,  it  being  sufficient  to  run  the  centrepunch 
dots  a  little  inside  the  line  at  the  end  of  the  block  on 
each  side.  The  lines,  A  A,  in  Fig.  339,  representing  the 
inside  jaw  faces,  should  also  be  a  little  taper,  first  to  allow 
of  fitting  the  strap  to  the  block  end,  and  next  to  make  the 


LINING   OR  MARKING   OUT   WORK. 


401 


fitting  of  the  brasses  into  the  strap  an  easier  operation. 
It  is  obvious  that,  if  the  inside  jaw  faces  of  the  strap  arc 
parallel  with  each  other,  so  soon  as  the  brass  is  reduced  to 
the  size  of  the  top  of  the  strap,  it  will  slide  clear  down  to 
its  bed ;  whereas,  if  those  faces  are  made  a  little  wider 
apart  at  the  open  end  than  at  the  crown  end,  the  brasses, 
after  entering  at  the  open  end,  will  have  metal  sufficient 
to  be  taken  off  them  (before  being  let  down  to  the  crown) 
to  permit  of  their  being  fitted  nicely  to  the  strap.  For 
these  reasons,  the  faces  of  the  strap,  A  A,  in  Fig.  339, 
are  made  wider  apart,  in  the  proportion  of  nearly  one- 

Fig.  339. 


-9- 

" 

EJL_  !  ' 

.  V"  ^  h  -r    '  •  —  i 

f~~                 r^s6 

j 


sixteenth  of  an  inch  of  taper  to  a  strap  having  a  jaw 
twelve  inches  long.  The  line,  D,  in  Fig.  339  represent- 
ing the  amount  of  metal  to  be  cut  out  of  the  crown  of 
the  strap,  should  only  need  that  sufficient  metal  come  off 
to  allow  that  face  to  just  true  up:  because  it  is  an  awk- 
ward face  to  operate  on,  and  it  is  much  easier  to  take 
any  surplus  metal  off  the  outside  crown  of  the  strap,  ns 
represented  by  the  line,  E,  in  Fig.  339.  The  lines,  F  F 
and  G  G,  are  marked  at  the  requisite  distance  from 
the  crown,  D,  of  the  strap,  with  a  square  resting  on  the 
face  of  the  marking  table.  The  round  corners  and 
34" 


402  COMPLETE  PRACTICAL  MACHINIST. 

curves  are  marked  off  with  the  compasses,  using  the  blocks 
of  wood  shown  in  our  lesson  on  marking  off  a  double 
eye,  previously  given.  The  finishing,  however,  of  such 
corners,  both  in  the  machine  and  in  the  vise,  is  usually 
done  to  a  small  sheet-iron  gauge.  Such  corners  may,  it 
is  true,  be  cut  on  a  slotting  machine  table  to  a  correct 
sweep  without  the  use  of  a  gauge;  and  there  are  many 
shaping  machines  with  special  attachments  for  the  same 
purpose. 

Our  next  operation  is  to  mark  out  the  keyway,  which 
is  performed  after  the  butt  end  of  the  rod  and  the  inside 
and  outside  of  the  strap  have  been  planed.  We  first, 
with  a  pair  of  compass  calipers,  which  are  better  for  the 
purpose  than  compasses,  mark  the  centre  of  the  strap 
edgeways,  and  then,  laying  it,  with  its  broad  surface  on 

Fig.  340. 


the  marking-off  plate,  we  mark  off  the  keyway  as  follows: 
In  Fig.  340  A  represents  the  table,  and  B  the  connecting 
rod  strap.  C  is  the  centre  line  of  the  strap,  and  therefore 
of  the  keyway ;  the  end,  E,  of  the  keyway  should  be  drawn 
the  necessary  distance  from  the  inside  crown  of  the  strap, 
as  denoted  by  the  dotted  vertical  line,  because  it  is  that 
distance  upon  which  the  thickness  of  the  brasses  depends. 
Hence  the  line,  E,  is  the  first  one  to  be  drawn  ;  then,  from 
the  line,  E,  we  mark  the  length  of  the  keyway,  and  strike 
the  line,  F ;  the  breadth  of  the  keyway  we  mark  by  setting 
the  compasses  to  the  radius  of  a  circle  whose  diameter  will 
be  equal  to  the  required  breadth  of  keyway.  Then  using 
the  centre  line  as  a  centre,  we  mark  the  circle,  G,  and 
(touching  its  diameter,  and  parallel  with  the  centre  line) 


I 


LINING   OR  NARKING   OUT  WORK.  403 

the  lines,  H  and  I,  thus  completing  the  marking  of  the 
keyway  on  the  strap. 

To  mark  off  the  oil  hole,  we  lay  the  strap  on  its  side 
face,  as  shown  in  Fig.  341,  and,  placing  a  straight  edge 
along  the  inside  crown  face  of  the  strap,  we  mark  a  line 
even  with  it  and  across  the  jaw  of  the  strap,  as  shown  at 
A,  and  from  that  we  mark  with  the  compasses  the  line,  B, 

the  distance  between  the  two 

*%•  34L  iK-ing  half  the  total    depth 

of  the  brasses,  or  what  is  the 
same  thing,  the  thickness  of 
the  crown  brass  (when  new) 
from  its  joint  face  to  its  bed- 
ding crown.  We  then,  with 
a  square  and  scriber,  carry 

the  line,  B,  over  to  the  centre  line  of  the  edges  of  the 
strap  (C  in  Fig.  340),  and  the  junction  of  the  two  is  the 
centre  of  the  oil  hole.  In  centre-punching  the  centre  for 
the  oil  hole  to  be  drilled,  make  a  deep  centrepunch  mark 
to  prevent  the  drill  from  running  to  one  side  and  thus 
deceiving  the  machinist  (who  may  have  to  line  up  the 
brasses  when  they  become  worn)  as  to  thickness  of  the 
liner  to  be  placed  behind  the  back  brass  to  keep  the  rod 
to  its  original  length. 

The  marking  of  the  keyway  in  the  butt  or  stub  end  of 
the  rod  is  performed  in  the  same  manner  as  that  of  the 
keyway  in  the  strap,  care  being  taken  to  make  the  edge 
of  the  keyway  nearest  to  the  end  of  the  rod  at  the  exact 
proper  distance  from  that  end  :  otherwise  the  amount  of 
space  left,  when  the  strap  is  in  its  place,  between  the  end 
of  the  rod  and  the  crown  of  the  strap  (which  regulates  the 
thickness  of  the  bra-ses),  will  not  be  correct,  and  the  oil 
hole  will  not  stand  in  its  correct  position  on  the  strap, 
unless  the  key  and  gib  are  made  to  suit  the  inaccuracy 
of  the  position  of  tlv  keyway  in  the  rod  end.  For  exam- 
p4e  :  Suppose  the  keyway  of  the  rod  to  appro ich  too  near 


404  COMPLETE  PRACTICAL  MACHINIST. 

the  rod  end;  then  the  strap  will,  if  the  gih  and  key  are 
made  of  the  proper  width  across,  as  at  A,  not  pass  suffi- 
ciently along  the  block  end,  and  there  will  he  too  much 
space  allowed  for  the  brasses,  and  the  oil  hole  will  stand 
too  near  the  crown  of  the  strap.  The  only  method  of  cor- 
recting this  defect  is  to  make  the  width  of  the  key  and 
gib,  at  A,  Fig.  342,  wider  to  the  necessary  amount,  and  to 
cut  the  keyways,  both  in  the  strap  and  the  rod  end,  wider, 
by  cutting  out  the  metal  on  the  edge  of  the  key  way  far- 
thest from  the  rod  end,  and  the  metal  on  the  edge  of  the 
key  way  in  the  strap  at  the  end  nearest  to  the  crown  of  the 
strap.  If  the  key  way  of  the  block  end  errs  in  the  oppo- 
site direction,  the  keyways  must  of  course  be  made  wider, 
the  metal  being  cut  out  in  the  exact  opposite  to  the.  above 
direction.  By  marking  out  the  two  keyways  as  above 
described,  we  have  no  occasion  to  take  any  account  of  the 
draw,  since  that  will  come  right  of  itself  when  the  brasses 
are  put  in  their  places  in  the  strap,  and  the  strap  is  put 
in  its  place  upon  the  rod  end.  In  marking  off  the  key  way 
in  the  rod  end  from  keyways  already  cut  in  the  strap,  the 
following  plan  must  be  adopted  :  Place  the  strap  upon  the 
rod  end,  leaving  the  space  between  the  rod  end  and  the 
crown  of  the  strap  narrower  than  is  required  to  receive 
the  brasses  (when  the  latter  are  new)  by  an  amount  eqnal 
to  the  amount  of  taper  there  is  in  the  full  length  of  the 
key,  and  mark  the  key  way  in  the  rod  end  even  with  the 
strap,  taking  no  account  of  the  draw  required  on  the 
keyway,  which  is  provided  for  in  the  position  in  which  the 
strap  is  placed  on  the  rod  end,  as  will  be  perceived  when 
we  consider  that  the  length  of  a  keyway  is  always  the 
width  of  the  key  and  gib,  at  A,  when  placed  together,  as 
shown  in  Fig.  342.  Hence,  when  marking  off  the  keyway 
in  the  rod  end  by  the  keyway  in  the  strap,  the  latter 
should  be  placed  in  the  position  in  which  it  will  stand 
when  the  key  and  gib  are  in  the  position  shown  in  Fig. 
342.  Supposing  then  the  gib  and  key  to  be  in  their  plac  s 


LINTNG   OR  MARKING   OUT   WORK. 


405 


in  the  rod  and  strap,  and  in  the  position  shown  in  Fig, 
342.  and  that  we  then  lift  the  key  up  so  that  it  will  stand 
in  the  position  shown  in  Fig.  343,  and  that  we  then  pull 
the  strap  as  far  off  the  block  end  of  the  rod  as  it  will 
come,  the  key  will  then  stand  in  its  correct  position,  and 
there  will  be  the  proper  amount  of  draw  in  the  keyway, 
both  in  the  strap  and  on  the  rod  end,  and  the  space 
between  the  end  of  the  rod  and  the  crown  of  the  strap 
will  also  be  correct.  To  mark  off  the  key  and  gib,  we 
proceed  as  follows :  After  the  key  ways  are  filed  out,  wo 
take  a  piece  of  thin  sheet  iron  and  fit  it  to  a  tight  fit  iu 


Fig.  342. 


Fig.  343. 


Fig.  344. 


the  breadth  or  thickness  of  the  keyway,  and  have  the 
thickness  of  the  key  and  gib  planed,  using  the  piece  of 
sheet  iron  as  a  gauge;  we  then  mark  off  the  key  on  both 
edges  to  the  proper  width  at  top  and  bottom,  and  hence 
give  it  the  correct  amount  of  taper.  We  also  have  the 
plain  or  straight  edge  (that  is,  the  edge  opposite  to  the 
jaws)  of  the  gib  planed  straight;  we  then  place  the  gib  and 
key  in  the  position  shown  in  Fig.  344,  and  mark  off  (from 
the  edge  face,  B,  of  the  key)  the  line,  A,  on  the  gib,  using 
the  compass  calipers  set  to  the  full  width  of  the  keyway 
in  the  strap  or  rod  end,  taking  no  account  of  the  draw. 


406 


COMPLETE  PRACTICAL   MACHINIST. 


Hence  the  key  and  gib  will,  when  in  the  positian  shown, 
just  fill  the  key  way.  The  width  between  the  jaws  of  the 
gib,  as  denoted  by  C,  should  be  marked  a  trifle  less  than 
is  the  extreme  outside  width  of  the  jaws  of  the  strap,  so  as 
to  allow  for  the  metal  taken  off  in  filing  up  the  outsides 
of  the  jaws  of  the  strap  and  off'  the  inside  of  the  jaws  of 
the  gib. 

To  mark  off  cylinder  ports  and  steam  valves:  Begin- 
ning with  the  cylinder,  we  place  in  the  exhaust  port  a 
centre-piece,  as  shown  in  Fig.  345,  in  which  A  represents 
the  steam  port,  B  B  the  cylinder  exhaust  port,  and  C  the 

Fig.  345. 


B 


E 


2) 


centre-piece  wedged  or  fastened  therein.  In  the  centre 
of  the  position  intended  for  the  ports,  we  mark  upon  the 
centre-piece  the  centre  line,  D,  and  from  the  points,  E,  F, 
we  mark  with  the  compasses  the  segments  of  circles  from 
which  the  width  of  the  steam-ports,  exhaust  port,  and 
bridges  are  marked,  the  lines  being  drawn  by  the  aid  of  a 
straight  edge.  We  mark  the  ends  of  the  ports  by  the  aid 
of  a  straight  edge  and  square.  To  mark  off  the  valve,  we 
may  either  plane  up  two  of  the  edges  and  mark  the  lines 
by  the  aid  of  a  square,  allowing  an  equal  amount  to  be 
taken  off  each  side  of  the  exhaust  port,  or  we  may  place  a 


LINING  OR  MARKING   OUT   WORK. 


407 


centre-piece  in  the  exhaust  port  of  the  valve,  and  perform 
all  the  marking-  off  before  any  of  the  planing  is  done,  the 
operation  being  shown  in  Fig.  346.  From  A  to  B  is  the 
width  of  the  exhaust  port  of  the  valve,  and  froiu  C  to  D 
on  each  side  is  the  lap  of  the  valve. 

It  is  found  that  valve  seats  (the  cylinder  faces  on  which 
the  valves  slide)  will  have,  when  they  become  worn,  a 


Fig.  346. 


groove  cut  across  the  bridges  between  the  ports  and  ex- 
tending along  the  face  beyond  on  each  side,  running  close 
to  the  edge  of  the  ports,  and  at  right  angles  to  the  lengths 
of  the  ports.  To  prevent  the  formation  of  this  groove,  it 
is  found  necessary  to  mark  after  the  face  of  the  valve  has 
been  planed  the  four  small  holes  (say  of  i  inch  diameter) 
shown  in  Fig.  346,  at  E,  E,  E,  E,  their  centres  coinciding 
with  the  edges  of  the  exhaust  port  of  the  valve. 


408 


COMPLETE  PRACTICAL  MACHINIST. 


To  mark  off  the  back  of  the  valve  where  the  slide 
spindle  frame  fits,  we  must  stand  it  on  the  marking  table, 
with  the  face  standing  perpendicularly  and  at  a  right 
angle  to  the  face  of  the  table,  and  draw  a  centre  line  on 
the  back  of  the  valve,  from  which  line  we  may  mark  off 
the  back  of  the  valve  to  the  necessary  conformation. 

TO   MARK   OUT   A    CONE   PULLEY. 

In  laying  out  cone  pulleys,  or  stepped  cones,  as  they  are 
sometimes  termed,  for  crossed  belts,  the  belt  will  have 
equal  tension  when  placed  to  run  on  any  of  the  cor- 
responding steps  of  the  cones,  providing  that  their  axial 
shafts  are  parallel  one  to  the  other;  that  the  largest  cone 
of  one  pulley  is  in  line,  or 

17**        Q/17 

/air,  with  the  smallest  cone  &' 

of  the  other;  and  that  the 
steps  of  the  cones  are  equal, 
so  that  a  line  drawn  from 
the  centre  of  the  faces  of  the 
two  end  steps  passes  also 
through  the  centre  of  the 
faces  of  all  the  other  steps, 
as  shown  in  Fig.  347,  by 
the  lines,  A  and  B.  It  fol- 
lows also  that  if  the  cones  were  plain,  that  is,  without 
steps,  the  tension  would  remain  equal  with  the  belt  at 
any  location  on  the  cone. 

In  Fig.  348,  A  and  B  represent  two  stepped  cones  con- 
nected by  the  two  belts,  C  and  D,  the  latter  running  upon 
the  middle,  and  the  former  on  the  end  cones,  the  belts 
being  crossed.  It  will  be  noted  that  in  consequence  of  the 
crossing  of  the  belt  it  has  contact,  on  both  the  top  and 
bottom  steps,  with  more  than  one-half  the  circumference 
of  the  steps,  but  the  variation  this  would  cause  in  the 
length  of  the  belt  is  too  slight  to  be  of  any  practical 
value;  hence  it  may  be  discarded.  Measuring  then  the 


LINING   OR  MARKING   OUT   WORK. 


409 


lengths  of  each  side  of  the  belt  from  the  centre-line  I  I  to 
the  centre-line  J  J,  we  shall  find  D  and  C  to  be  equal ; 
and  if  we  assume  the  diameter  of  the  step  marked  1  to 
be  10  inches,  and  that  of  the  smallest,  marked  3,  to  be  4 
inches,  the  half  of  their  added  circumferences  will  be 
21*99.  In  this  case,  the  sizes  of  the  middle  cones,  marked 

Fig.  348. 


2,  will  be  7  inches,  and  the  half  of  their  added  circumfer- 
ences (and  this  is  the  part  of  the  cones  around  which  the 
belt  would  lap)  will  also  be  21*99  inches;  hence,  the  sum 
of  the  arcs  of  contact  of  the  belt  around  the  pulley  being 
equal  in  both  cases,  and  the  lengths  of  the  sides  of  the 
belt  being  equal,  it  is  obvious  that  the  tension  of  the  belt 
will  also  remain  equal. 
35 


410 


COMPLETE  PRACTICAL  MACHINIST. 


If  the  two  cones  are  to  be  connected  by  an  open  or  un- 
crossed belt  the  case  is  different,  because  the  length  of  the 
side  of  the  belt,  measured  from  centre-line  to  centre-line 
of  the  steps  at  their  perimeters,  will  vary  as  the  sizes  of  the 
steps  vary.  Thus,  if  we  apply  a  pair  of  compasses  at 
K  L  and  at  M  N,  we  shall  find  the  distance  K  L  the 
shorter,  and  as  a  result  the  belt  would  have  less  tension 
when  on  those  steps,  and  the  degree  to  which  this  will 
exist  will  be  in  proportion  to  the  length  of  the  belt  and 
the  variation  in  the  sizes  of  the  steps  of  the  cone. 

To  remedy  this  defect,  the  cones  are  laid  off,  as  shown 
in  Fig.  349,  a  6  representing  the  axial  line  of  the  cone; 


Fig.  349. 


h  ...-- 


c,  d,  e,  fj  g  are  tha  centre-lines  of  the  steps  and  h,  i  a 
curve,  whose  radius  will  vary  according  to  the  conditions. 
The  rule  for  finding  it  is,  subtract  twice  the  distance  be- 
tween the  centres  of  the  two  cones  from  the  total  length 
of  the  belt  (measured  over  the  end  steps)  and  divide  the 
remainder  by  6'2832,  the  quotient  is  the  radius  of  curve 
required.  The  process  is  to  mark  from  the  centre-line  a, 
b  (Fig.  349)  the  radius  of  the  end  steps  of  the  cone,  as  at 
h,  i,  to  find  the  required  centre  of  curve  from  h,  i,  and 
the  intersection  of  the  curve  with  the  centre-lines  of  the 
steps,  as  at  o,  o,j,  is  the  radius  for  the  intermediate  steps 
of  the  cone. 


CHAPTER      XIX. 

TO   CALCULATE   THE   SPEED   OF   WHEELS,    PULLEYS,    ETC. 

MULTIPLY  the  speed  of  the  driving-wheel  by  the  num- 
ber of  teeth  it  contains,  and  divide  by  the  speed  required 
by  the  driven  wheel. 

Example  1. — If  a  wheel  contains  50  teeth  and  makes 
25  revolutions  per  minute,  what  number  of  teeth  must  a 
wheel  contain  to  gear  into  it  and  make  125  revolutions 
per  minute? 

50  X  25  =  1250  -r-  125  =  10.  Ans.  10  teeth. 

Example  2. — A  wheel  contains  90  teeth  and  makes  120 
revolutions  per  minute,  how  many  teeth  must  a  wheel  con- 
tain to  gear  into  it  and  make  240  revolutions  per  minute? 
90  X  128  =  10800  -*-  240  =  45.         Ans.  45  teeth. 

Example  3. — A  wheel  contains  45  teeth  and  makes  240 
revolutions  per   minute,   how  many  teeth   must  a  wheel 
geared  into  it  contain  to  run  120  revolutions  per  minute? 
45  X  240  =  10800  -r-  128  =  90.        Ans.  90  teeth. 

In  the  case  of  pulleys  or  band- wheels  the  rule  is  the 
same,  except  that  the  diameter  of  the  wheel  is  taken 
instead  of  the  number  of  teeth. 

Example  1. — A   driving-wheel  makes   120   revolutions 
per  minute  and  is  24  inches  in  diameter,  what  size  pulley 
must  I  employ  to  obtain  60  revolutions  per  minute? 
120  X  24  =  2880  -=-  60  =  48.  Ans.  48  inches. 

Example  2. — A  driving-wheel  four  feet  in  diameter 
makes  245  revolutions  per  minute,  what  size  pulley  must 

I  use  to  obtain  45  revolutions? 

411 


412  COMPLETE  PRACTICAL  MACHINIST. 

Diameter  of  wheel 
in  inches. 

48  X  245  =  11760  -4-  45  =  248.     Ans.  248  inches. 

Example  3. — A    driving-wheel    makes   182   revolutions 
per  minute,  and  is  15  inches  in  diameter,  what  size  pulley 
do  I  require  to  make  145  revolutions? 
182  X  15  =  2730  -=-  145  =  18.965. 

Ans.  A  pulley  18  T9(f0   in.  in  diameter. 

Another  rule  which  will  answer,  whether  we  employ  a 
single  pair  or  two  pair  of  pulleys,  is  as  follows  : 

Divide  the  speed  you  require  to  run  by  the  speed  of  the 
driving-shaft,  and  the  quotient  will  be  the  proportion 
between  the  revolutions  of  the  driving-shaft  and  the  revo- 
lutions required.  Then  take  any  two  numbers  that  will, 
when  multiplied  together,  form  a  sum  equal  to  that  propor- 
tion, and  one  of  such  numbers  will  form  the  relative  sizes 
for  one  of  the  pairs  of  pulleys,  and  the  other  of  such 
numbers  will  form  the  relative  sizes  for  the  other  pair  of 
pulleys. 

Example. — It  is  required  to  run  a  machine  1200  revo- 
lutions per  minute,  the  driving-shaft  makes  120  revolu- 
tions per  minute,  what  sizes  of  pulleys  shall  be  used? 

Revolutions    Revolutions  of    Proportion  of 
required,      driving-shaft.  speed. 

1200  -T-      120    =  10 

Then  5    X    2    =  10 

or  4    X    2^  =  10 

or  3i  X    3    =  10 

So  that  the  proportion  being  ten  to  one,  we  may  use  two 
wheels  of  any  sizes,  providing  that  the  one  on  the  driv- 
ing-shaft is  ten  times  as  large  as  the  one  on  the  machine: 
or  since  5X2  =  10,  we  may  place  on  the  driving-shaft  a 
pulley,  say  five  feet  in  diameter,  and  belt  it  to  one  a  foot 
in  diameter,  forming  the  proportion  between  the  first  pair 
of  pulleys  of  five  to  one.  Our  next  pair  of  pulleys  must 


SPEED   OF   WHEELS,  PULLEYS,  ETC.  413 

be  two  to  one,  that  is  to  say,  we  may  use  a  two  foot  and  a 
one  foot  pulley,  a  four  and  a  two  foot,  or  any  others,  so 
that  one  is  twice  as  large  as  the  other.  Or  again,  since 
4  X  2?  =  10,  we  may  use  a  four  foot  pulley,  or  the  driving- 
shaft  belted  to  a  foot  pulley,  or  a  24  inch  one  belted  to  a 
6  inch  one,  the  proportion  in  either  case  being  4  to  1,  ihen 
for  the  second  pair  we  may  employ  a  12  and  a  6  inch,  or 
a  24  and  a  12,  or  any  two  pulleys  we  may  have  on  hand, 
so  that  one  is  twice  as  large  as  the  other.  It  is  obvious 
that  when  the  speed  required  is  greater  than  that  of  the 
driving-shaft,  the  large  pulleys  are  the  driving  and  the 
small  ones  are  the  driven  pulleys. 


35 


CHAPTER   XX. 

HOW  TO  SET  A  SLIDE  VALVE. 

IN  setting  a  slide  valve,  we  are  confronted  with  the 
following  considerations : 

Our  object  is  to  cause  the  admission  to  expansion  of  and 
exhaust  from  the  cylinder  of  the  steam  equal  for  each 
stroke.  This,  however,  we  are  unable  to  attain,  because  of 
the  angle  of  the  connecting  rod.  If  we  set  the  valve  so  that 
the  exhaust  commences  in  the  same  relative  position  of  the 
piston  at  one  stroke  as  compared  to  the  other,  the  valve 
will  not  admit  the  steam  to  the  cylinder  in  the  same  relative 
position  of  the  piston  at  one  end  of  the  stroke  as  compared 
to  the  other — that  is  to  say,  the  valve  being  set  so  that  the 
exhaust  will  take  place  when  the  piston  has  moved  an 
equal  number  of  inches  of  the  stroke  at  either  end  of  the 
cylinder,  the  steam  port,  when  the  crank  is  on  the  respect- 
ive dead  centres,  will  be  wider  open  at  one  end  than  at 
the  other.  Then,  again,  if  we  set  the  valve  so  that  the 
exhaust  commences  at  an  equal  part  of  the  stroke  at  either 
end  of  the  cylinder,  the  exhaust  port  will  be  wider  open 
when  the  crank  is  on  one  dead  centre  than  it  will  when 
the  crank  is  on  the  other  dead  centre.  Whereas,  if  we  set 
the  valve  so  that  the  steam  port  at  each  end  is  open  to  an 
equal  amount  when  the  crank  is  on  either  respective  dead 
centre,  the  exhaust  port  will  also  be  open  at  each  end  to 
an  equal  amount  when  the  crank  is  on  the  dead  centre. 
Thus,  by  setting  the  vJve  so  that  it  has  an  equal  amount 
of  lead  at  each  end  of  the  piston  stroke,  the  exhaust  ports 
will  be  open  to  an  equal  amount  when  the  piston  com- 
414 


HOW  TO  SET  A  SLIDE   VALVE.  415 

mences  its  return  stroke  at  either  end  of  the  cylinder.  It 
is  always,  therefore,  preferred  to  set  the  valve  so  that  it 
shall  have  lead  to  an  equal  amount  when  the  crank  is  on 
the  dead  centre. 

If  the  stroke  of  a  valve  is  made  to  be  twice  the  width  of 
the  steam  port  added  to  twice  the  amount  of  the  lap,  it  will 
be  found  that  the  steam  port  at  the  end  of  the  cylinder 
farthest  from  the  crank  will  not  open  fully,  while  that 
nearest  to  the  crank  will  have  the  valve  travel  past  it  to 
an  equal  amount ;  the  degree  of  this  difference  becoming 
greater  as  the  amount  of  the  lap  is  increased,  and  hence,  as 
the  amount  of  the  lead  or  angular  advance  of  the  eccentric 
becomes  greater. 

The  exhaust  of  the  steam  will,  when  the  lead  of  the 
valve  is  equal  at  each  end  of  the  stroke,  take  place  earlier 
in  the  stroke  in  the  front  end  of  the  cylinder — that  is,  the 
end  the  farthest  from  the  crank — than  it  will  at  the  back 
end,  while  the  steam  will  work  expansively  during  a 
greater  part  of  the  stroke  when  it  is  in  the  back  end  than 
will  be  the  case  wlien  it  is  in  the  front  end  of  the  cylinder. 
Having  noted  these  facts,  wre  may  proceed  to  set  a  valve, 
the  first  operation  being  to  carefully  remove,  by  blowing 
or  washing  out,  any  filings  or  scrapings  that  may  have 
lodged  in  the  ports  while  operating  upon.  The  valve-seat, 
or  the  cylinder,  the  bore  of  the  cylinder,  the  valve-face, 
and  the  face  of  its  seat,  having  been  carefully  cleaned  and 
then  oiled,  we  may  connect  the  various  parts,  and  find  and 
mark  the  dead  centres  or  dead  points  of  the  stroke  as 
follows : 

In  Fig.  350  A  represents  the  guide-bar,  B  the  guide- 
block,  C  the  fly-wheel,  D  the  crank,  E  the  eccentric,  and 
F  the  centre-line  of  the  connecting-rod  of  an  engine 
intended  to  run  in  the  direction  of  the  arrow. 

Giving  the  w7heel  a  turn  or  two  in  the  direction  in  which 
it  is  intended  to  run,  we  allow  it  to  come  to  rest,  so  that 
the  motion-block  B  will  be  at  very  nearly  the  end  of  its 


416  COMPLETE  PRACTICAL  MACHINIST. 


HOW  TO  SET  A   SLIDE   VALVE.  417 

stroke  on  the  guide-bar  A,  and  then  placing  the  edge  of  a 
straight  edge  along  the  end  of  the  guide-block  B,  the 
straight  edge  at  the  same  time  overlapping  the  face  of  the 
guide-bar,  we  mark  on  the  face  of  the  latter  the  line  1, 
which  will  thus  be  quite  even  with  the  end-face  of  the 
guide-block.  We  then  (after  chalking  it  to  make  the 
marks  show  plainly)  mark  on  the  face  of  the  wheel  the 
line  2,  which  should  be  true  with  the  centre  of  the  main 
shaft,  but  which  can  be  marked  from  the  rim  of  the  wheel 
with  a  pair  of  compass  calipers,  providing  that  rim  has 
been  trued  up  in  the  lathe.  We  next,  with  a  piece  of  iron 
wire  or  rod  bent  as  shown  by  G,  mark  at  some  fixed 
point,  such  as  shown  at  H ;  make  a  centre-punch  mark, 
and  resting  one  end  of  the  scriber  G  in  the  fixed  centre- 
punch  mark,  we  scribe  with  the  other  end  upon  the  edge 
of  the  wheel  the  line  3,  as  shown  in  the  illustration.  Our 
next  operation  is  to  move  the  wheel  forward  in  the  direc- 
tion in  which  it  is  to  run,  so  that  the  crank  will  move  to 
the  dead  centre,  and  the  guide-block  will  leave  the  line  1, 
as  shown  in  Fig.  o51,  and  the  motion  of  the  wheel  being 


Fig.  351. 


continued,  the  guide-block  will  return  to  the  mark  1,  the 
wheel  being  moved  very  slowly  indeed,  so  that  there  will  be 
no  trouble  so  to  move  it  that  the  end  of  the  guide-block  will 
come  to  rest  exactly  fair  with  line  1.  If,  by  chance,  the  end 
of  the  guide  should  move  past  the  line,  the  wheel  should  be 
turned  well  back — that  is  to  say,  back  to  the  end  of  the 
stroke — and  again  moved  slowly  forward  till  it  comes  fair 
with  the  line  1.  The  object  of  thio  is  that  the  guide-block 
shall  always  approach  the  line  moving  in  the  direction  in 
which  it  will,  while  parforming  that  stroke,  move  when  the 


418  COMPLETE   PRACTICAL  MACHINIST. 

engine  is  at  work,  so  that  all  the  working  parts  will  be 
brought  to  a  bearing  in  the  direction  in  which  they  will 
bear  when  at  work,  and  hence  any  spring  or  lost  motion  in 
any  of  the  parts  will  not  affect  the  setting  of  the  valve. 

Suppose,  for  instance,  there  was  even  a  trifling  amount 
of  play  in  the  eccentric  or  any  of  the  bolts,  and  that  the 
end  of  the  guide-block  on  its  return  stroke  having  moved 
a  trifle  past  the  line  1,  we  move  the  wheel  backward  a 
trifle  to  correct  the  error,  thus  making  the  block  approach 
the  line  from  the  opposite  direction  to  what  it  will 
approach  it  when  at  work  and  travelling  on  that  stroke, 
then  part  of  the  movement  of  the  wheel  will  have  been 
lost  (so  far  as  the  movement  of  the  guide-block  is  con- 
cerned), having  been  expended  in  taking  up  the  lost 
motion.  It  makes  no  difference  if  the  engine  is  to  run  both 
ways,  for  in  that  case  we  observe  the  same  precaution  in 
moving  the  wheel,  setting  the  valve  in  the  forward  gear, 
and  then  trying  it  in  the  backward  gear,  and  dividing  the 
difference,  if  there  be  any. 

To  proceed,  then,  the  guide-block  having  returned  even 
with  the  line  1,  we  take  our  wire  scriber,  rest  one  end  in 
the  fixed  point,  and  with  the  other  end  mark  on  the  edge- 
lace  of  the  wheel  line  4,  which  will  then  occupy  the  place 
that  line  3  does  in  our  engraving.  Our  next  duty  is  to  find 
die  centre  between  lines  3  and  4  as  shown  in  Fig.  352,  which 

Fig.  352.  Fig.  353. 


we  obtain  from  lines  3  and  4,  and  which  we  mark  with  a 


HOW  TO  SET  A  SLIDE    VALVE.  419 

fine  centre-punch  mark,  as  shown  at  5.  And  it  will  readily 
be  perceived  that  if  we  move  the  wheel  round  so  that  the 
scriber  G  resting  in  the  fixed  centre-point  as  shown  in  Fig. 
353,  the  end  will  be  true  with  centre-punch  mark  5,  the 
motion-block,  and  hence  the  piston  and  crank,  will  be 
exactly  on  the  dead  centre  at  that  end  of  the  stroke. 

We  next  move  the  wheel  around,  so  that  the  guide-block 
will  be  nearly  at  the  end  of  its  stroke  at  the  opposite  end 
of  the  guide-bar,  and  mark  a  Iin3  occupying  the  same  rel- 
ative position  at  that  end  as  line  1  does  at  the  other  end, 
and  repeat  the  whole  previous  operation,  thus  marking 
new  lines  corresponding  to  the  linos  2,  3,  4,  and  5,  but  on 
the  opposite  diameter  of  the  wheel ;  thus  we  shall  obtain  the 
lines  6  and  7  iii  Fig.  350,  and  from  them  the  centre-punch 
mark  8,  which  will  serve  the  same  purpose  at  that  end  of 
the  stroke  as  does  the  centre-punch  5  at  the  opposite  end. 

Our  next  procedure  is  to  provide 
a  small  wooden  wedge,  such  as  is 
shown  in  Fig.  354,  making  one  end 
of  a  thickness  equal  to  about  half 
the  amount  of  lead  it  is  intended  to 
give  the  valve,  and  the  other  about 
twice  as  thick  as  the  intended 
amount  of  lead,  its  length  being  about  three  inches. 
We  then  move  the  wheel  in  the  direction  in  which  it  is 
intended  to  run,  until  the  scriber,  one  point  resting  in 
the  fixed  centre-punch  mark,  the  other  will  be  exactly 
even  with  centre-punch  mark  5,  and  the  engine  will  be  on 
the  forward  or  front  dead  centre. 

We  are  now  ready  to  set  the  eccentric,  and  the  questio  i 
arises,  which  way  the  engine  ought  to  run  ?  We  have  per- 
formed all  our  operations  thus  far  with  a  view  to  have  the 
engine  run  in  the  direction  denoted  by  the  arrow  in  350 ; 
for  had  the  engine  been  intended  to  run  in  the  opposite 
direction,  we  should  have  drawn  line  1  while  the  guide- 
block  was  in  the  same  position  on  the  guide-bar,  but  with  the 


420 


COMPLETE  PRACTICAL  MACHINIST. 


crank  on  the  other  side  of  the 
game  dead  centre.  The  direc- 
tion of  arrow  C,  Fig.  355,  is  the 
correct  one  in  which  an  engine 
should  run,  if  circumstances 
permit,  for  the  following  rea- 
sons:  in  Fig.  355,  if  we"  suppose 
A  to  represent  the  centre-line  of 
the  connecting-rod,  and  the  en- 
gine to  be  running  in  the  direc- 
tion of  the  arrow  B,  then  the 
strain  on  the  connecting-rod 
will  be  in  a  direction  tending  to 
compress  it,  the  strain  on  the 
guide-bar  being  in  the  direction 
to  force  the  cross-head  guide- 
blocks  down  upon  the  guide- 
bars,  and  hence  to  produce  the 
most  friction  ;  whereas  if  the 
engine  was  running  in  the  direc- 
tion denoted  by  the  arrow  C, 
the  strain  upon  the  connecting- 
rod  will  be  one  in  a  direction 
to  pull  it  apart,  and  hence  to 
lift  it  and  the  cross-head  guidc- 
blocks  from  the  guide-bars,  so 
that  the  centre  line  of  the  con- 
necting-rod would  stand  in  the 
direction  of  the  line  D.  When 
the  crank  is  on  the  other  side 
of  the  dead  centres,  the  same 
effect  in  either  case  is  pro- 
duced. Now  it  is  quite  true 
that  so  long  as  the  guide- 
blocks  fit  to  the  guide-bars, 
the  rod  cannot  move  in  any 


HOW  TO  SET  A  SLIDE   VALVE.  421 

direction,  but  the  spring  of  the  various  parts,  the  direction 
of  which  is  determined  by  the  direction  of  the  strain,  is 
sufficient,  even  when  the  engine  is  new,  and  hence,  there 
is  no  play  in  the  guide-blocks  to  (if  the  engine  is  running 
in  the  direction  shown  by  the  arrow  C  in  Fig.  355)  relieve 
the  guide-bars  of  the  friction  due  to  the  weight  of  the  con- 
necting-rod. The  only  objection  to  be  advanced  against 
running  an  engine  in  the  direction  to  relieve  the  slides  of 
the  weight  of  the  connecting-rod  is,  that  in  such  case  the 
wear  of  gibs  of  the  cross-head  will  be  mainly  on  the  under- 
neath side,  and  that,  therefore,  the  play  should  be  taken 
up  on  that  side,  and  the  set  screws  provided  for  that  purpose 
will,  on  many  engines,  be  somewhat  difficult  to  get  at. 

Having  determined,  then,  the  direction  in  which  the 
engine  is  to  be  run,  we  place  our  eccentric  so  that  its 
throw  line  (K,  in  Fig.  350)  will  stand  sufficiently  in 
advance  (in  the  direction  in  which  the  engine  is  to  run) 
to  let  the  front  port  open  to  the  required  amount  of  lead, 
and  fasten  it  there  with  the  set-screw.  We  then  measure 
the  amount  of  lead  there  is  on  the  valve  when  the  eccentric 
is  so  set,  by  chalking  the  faces  of  the  wooden  wedge,  and 
inserting  it  in  the  opening  or  lead  of  the  port,  as  shown  in 
Fig.  356,  putting  it  in  between  the  edge  of  the  val  ve  and 

Fig.  356. 

HORIZONTAL  SECTION 


the  edge  of  the  port  until  it  is  a  snug  fit,  but  not  forcing  it 
in  (which  would  compress  the  wood).     When  the  wedge  is 
36 


422  COMPLETE  PRACTICAL  MACHINIST. 

home  it  should  be  moved  edgeways,  and  then  taken  out, 
and  the  steam  port  edge  will  have  left  a  mark  on  the 
wedge,  evidencing  how  far  the  wedge  entered,  and  there- 
fore the  precise  amount  of  the  lead  at  that  end.  We  then 
move  the  wheel  forward  until  the  crank  is  on  the  other  dead 
centre — that  is  to  say,  until  the  centre-punch  mark  No.  8 
conies  exactly  even  with  the  scriber  point  G— and  try  the 
wedge  in  the  back  port,  and  if  it  enters  at  the  same  dis- 
tance as  it  did  at  the  front  port,  the  valve  is  set. 

If,  however, 'there  is  found  to  be  more  lead  at  one  end 
than  at  the  other,  it  demonstrates  that  the  eccentric  rod  is 
not  the  correct  length ;  if  the  front  port  has  the  most  lead, 
the  eccentric  rod  is  too  short,  and  vice  versa.  Locomotives 
and  other  engines,  in  which  the  height  of  the  main  shaft 
will  vary  in  its  relation  to  the  height  of  the  cylinder 
according  to  the  weight  of  the  engine  or-  its  load  (as  of 
fuel,  water,  etc.),  should  have  their  valves  set  with  the  load 
on  and  the  engine  in  its  working  position,  or  moved  along 
the  rail,  instead  of  revolving  the  wheel  with  the  engine 
lifted  off  the  rail. 

It  Is  an  excellent  plan  after  an  engine  valve  is  set,  to 
take  the  scriber  G,  in  Fig.  350,  and  making  it  exactly  C 
inches  long  from  point  to  point  (so  that  its  length  may 
always  be  known  and  remembered)  rest  one  point  on  some 
part  of  the  steam-chest,  and  in  a  centre-punch  mark  provided 
for  the  purpose,  and  with  the  other,  mark  a  line  on  the  slide- 
spindle,  when  the  engine  is  on  each  dead  centre.  Then 
put  a  centre-punch  mark  on  the  slide-spindle.  Thus  with 
the  gauge  applied  to  the  steam-chest  and  slide-spindle,  the 
valve  may  be  set,  in  cases  of  necessity,  without  taking  the 
steam-chest  cover  off.  It  is  better,  however,  to  remove  the 
steam-chest  cover  if  circumstances  permit. 


CHAPTER  XXI. 

PUMPS. 

PUMPS  are  commonly  divided  into  three  classes,  ths 
suction  pump,  the  force  pump,  and  the  suction  and  force 
pump. 

SUCTION   PUMPS. 

A  suction  pump  causes  water  to  raise  itself,  by  relieving 
its  surface  of  the  pressure  of  the  column  of  air  resting  upon 
it.  The  principle  upon  which  it  acts  may  be  explained  as 
follows : 

The  surface  of  all  water  exposed  to  the  air  has  the  press- 
ure of  the  air  or  atmosphere  resting  upon  it;  if,  therefore, 
one  end  of  a  pipe  or  tube  be  lowered  into  water,  and  the 
other  end  be  closed  by  means  of  a  valve  or  other  device, 
and  the  air  contained  in  the  pipe  be  drawn  out,  it  is 
evident  that  the  surface  of  the  water  within  the  pipe -will 
be  relieved  of  the  pressure  of  the  atmosphere  $  and  there 
will  be  no  resistance  offered  to  the  water  to"  prevent  its 
ascending  the  pipe.  The  water  outside  of  the  pipe,  still 
having  the  pressure  of  the  atmosphere  upon  its  surface, 
therefore  forces  water  up  into  the  pipe,  supplying  the  place 
of  the  excluded  air.  The  water  inside  the  pipe  will  rise 
above  the  level  of  that  outside  of  the  same  in  exact  propor- 
tion to  the  amount  to  which  it  is  relieved  of  the  pressure 
of  the  air,  so  that,  if  the  first  stroke  of  a  pump  reduce  the 
pressure  of  the  air  contained  in  the  pipe  from  15  Ibs.  on 
the  square  inch  (which  is  its  normal  pressure)  to  14  Ibs. 
per  inch,  the  water  will  be  forced  up  the  pipe  to  the 
distance  of  about  2i  feet,  because  a  column  of  water 

423 


424  COMPLETE  PRACTICAL  MACHINIST. 

an  inch  square  and  21  feet  high  is  equal  to  about  1  Ib.  in 
weight. 

It  is  evident  that,  upon  the  reduction  of  the  pressure  of 
the  air  contained  in  the  pipe  from  15  to  14  Ibs.  per  square 
inch,  there  would  be  (unless  the  water  ascended  the  pipe) 
an  unequal  pressure  upon  its  surface  inside  as  compared  to 
that  outside  of  the  pipe ;  but  in  consequence  of  the  water 
rising  2^  feet  in  the  pipe,  the  pressure  on  the  surface  of  the 
water,  both  inside  and  outside,  is  evenly  balanced  (taking 
the  level  of  the  outside  water  to  be  the  natural  level  of  the 
water  inside),  for  the  pressure  upon  the  water  exposed  to 
the  full  atmosphere  will  be  15  Ibs.  upon  each  square  inch 
of  its  surface;  while  that  upon  the  same  plane,  but  within 
the  pipe,  will  sustain  a  column  of  water  2}  feet  high 
(weighing  1  Ib.)  and  14  Ibs.  pressure  of  air,  making  a 
total  of  15  Ibs.,  which  is,  therefore,  an  equilibrium  of 
pressure  over  the  whole  surface  of  the  water  at  its  natural 
level. 

If,  in  consequence  of  a  second  stroke  of  the  pump,  the 
air  pressure  in  the  pipe  is  reduced  to  13  Ibs.  per  inch,  the 
water  will  rise  up  it  another  2}  feet,  and  so  on  until  such 
time  as  the  rise  of  the  column  of  water  within  the  pipe  is 
sufficient  to  be  equal  in  weight  to  the  pressure  of  the  air 
upon  the  surface  of  the  water  without;  hence  we  have  only 
to  determine  the  height  of  a  column  of  water  necessary  to 
weigh  15  Ibs.  per  square  inch  of  area  at  the  base  of  the 
column  to  ascertain  how  far  a  suction  pump  will  cause 
water  to  rise,  and  this  is  found  by  calculation  or  measure- 
ment to  be  a  column  nearly  34  feet  high.  It  becomes  ap- 
parent, then,  that,  however  high  the  pipe  may  reach  above 
the  water  level,  the  water  cannot  rise  more  than  34  feet 
up  the  pipe,  even  though  all  the  air  be  excluded  within  the 
pipe,  because  the  propelling  force,  that  is,  the  atmospheric 
pressure,  can  only  raise  a  column  of  water  equal  in  weight 
to  itself.  It  is  found,  however,  in  practice,  to  be  an  ex- 
cellent auction  pump  which  will  raise  water  thirty  feet 


PUMPS.  425 

From  this  it  will  be  perceived  that  the  terms  "drawing 
water  "and  "suction  pump  "  do  not  accurately  represent 
the  principles  upon  which  this  pump  performs  its  duty; 
and  it  would  be  much  more  proper  to  call  it  a  "displace- 
ment pump,"  since  its  action  is  simply  to  enable  the  water 
to  rise  by  displacing  the  air  from  its  surface. 

The  duty  of  this  pump  is,  therefore,  in  the  first  place,  to 
extract  the  air  from  the  Auction  pipe,  and,  in  the  second 
place,  to  discharge  the  water  from  its  barrel  through  the 
medium  of  valves  in  such  a  manner  that  the  column  of 
water  in  the  suction  pipe  is  at  all  times  entirely  excluded 
from  the  pressure  of  the  atmosphere. 

FORCE    PUMPS. 

A  force  pump  is  one  by  means  of  which  the  water  is  ex- 
pelled from  the  pump  barrel  and  through  the  delivery  pipe 
by  means  of  the  mechanical  force  applied  to  the  pump 
piston  or  plunger;  the  amount  of  power  required  to  drive 
such  a  pump  will,  therefore,  depend  at  all  times  upon  the 
height  to  which  the  water  is  required  to  be  forced.  When 
a  pump  is  arranged  to  draw  the  water,  and  force  it  after  it 
has  left  the  pump  barrel,  it  is  termed  a  suction  and  force 
pump ;  but  if  the  water  merely  flows  into  it  in  consequence 
of  the  level  of  the  water  supply  being  equal  to  or  above 
that  of  the  top  of  the  pump  barrel,  it  is  termed  simply  a 
force  pump.  Hence  a  suction  pump  performs  its  duty  in 
causing  the  water  to  rise  to  the  pump,  a  force  pump  is  one 
which  performs  its  duty  in  expelling  water  from  its  barrel, 
and  a  suction  and  force  pump  is  one  which  performs  both 
duties  alternately. 

All  pumps  require  a  suction  and  a  discharge  valve,  the 
suction  valve  being  so  arranged  as  to  open  to  admit  the 
water  into  the  pump  barrel  while  the  pump  piston  or 
plunger  is  receding  from  that  valve,  and  to  close  as  soon 
as  the  plunger  rtops  or  reverses  its  motion.  The  delivery 
valve  is  so  arranged  that  it  closes  as  the  pump  plunger  or 


426  COMPLETE  PRACTICAL  MACHINIST. 

piston  recedes  from  it,  and  opens  when  the  same  approaches 
it.  When,  therefore,  the  pump  piston  recedes  from  the 
suction  valve,  the  latter  opens  and  admits  the  water;  and 
when  the  piston  reverses  its  motion,  the  suction  valve 
closes,  and  the  descent  of  the  pump  piston  forces  the  water 
through  the  delivery  valve,  that  being  its  only  possible 
mode  of  egress  from  the  barrel  of  the  pump. 

The  arrangement  of  the  valves  may  be  the  same  for  a 
force  as  for  a  suction  pump  (although  it  is  advisable,  in 
some  cases,  to  place  an  additional  valve  to  a  force  pump 
to  prevent  the  pump  piston  from  receiving  the  force  of  the 
water  in  the  delivery  pipe),  the  only  difference  being  that 
the  water  is  permitted  to  flow  freely  away  from  a  suction 
pump,  whereas  it  is  confined  to  the  delivery  chamber  or 
pipe  in  a  force  pump,  so  as  to  force  it  to  the  required  height 
or  pressure,  as  the  case  may  be. 

PISTON  PUMPS. 

A  piston  pump  is  one  in  which  the  water  is  drawn  or 
forced  by  means  of  the  piston  fitting  the  barrel  of  the 
pump  air-tight,  which  is  most  commonly  done  by  providing 
the  piston  with  two  cupped  leathers,  formed  by  being 
pressed  in  a  die  made  for  the  purpose.  The  leather  is 
soaked  in  the  water  before  being  placed  in  the  die,  and 
is  allowed  to  remain  in  the  die  until  it  is  dry,  when  it 
will  be  sufficiently  hard  to  admit  of  being  turned  in  the 
lathe. 

The  capacity  of  a  piston  pump  is  its  area  multiplied  by 
the  length  of  its  stroke;  but  it  must  be  remembered  that 
all  pumps  throw  less  water  than  their  capacity,  the  defi- 
ciency ranging  from  20  to  40  per  cent.,  according  to  the 
quality  of  the  pump.  This  loss  arises  from  the  lift  and  fall 
of  the  valves,  from  inaccuracy  of  fit  or  leakage,  and  in  many 
cases  from  there  being  too  much  space  between  the  valves 
and  piston  or  plunger. 


PUMPS.  427 

A  plunger  pump  is  one  in  which  a  plunger  is  used  in 
place  of  a  piston,  the  gland  through  which  the  plunger 
moves  serving  as  its  guide,  and  also  keeping  it  air  and 
water-tight.  The  plunger  is  made  smaller  in  diameter 
than  the  bore  of  the  pump  barrel,  so  that  the  capacity  of 
such  a  pump  is  the  area  of  the  end  face  of  its  plunger  mul- 
tiplied by  the  length  of  its  stroke,  because  the  pump  acts 
by  reason  of  the  displacement  caused  by  the  plunger 
entering  the  barrel.  Pump-plungers  should  always  be 
draw-filed  lengthways  to  prevent  them  from  wearing  away 
the  packing  so  rapidly.  It  is  always  advisable  in  this 
kind  of  pump  to  allow  as  small  an  amount  of  space  between 
the  plunger  and  barrel  as  possible,  for  the  following 
reason:  When  the  plunger  becomes  worn,  it  is  necessary 
to  turn  it  up  again  in  the  lathe,  thus  reducing  its  diameter. 
The  result  is  that  there  is  so  much  air  in  the  pump,  between 
its  barrel  and  the  plunger,  that  it  expands  as  the  plunger 
leaves  the  barrel  and  is  merely  compressed  by  the  plunger 
returning,  so  that  the  pump  becomes  very  ineffective,  and 
finally  ceases  to  pump  at  all.  If  the  pLimp,  in  such  a 
case,  be  primed  with  water  each  time  it  is  started,  it  may 
draw  water,  but  not  to  its  full  capacity,  as  the  air  will  re- 
main in  the  pump  barrel  until  such  time  as  it  may  become 
absorbed  by  the  water. 

Suction  valves  for  all  pumps  should  be  made  as  large  in 
area  as  it  is  possible  to  get  in,  so  that  they  will  not  require 
to  lift  much  to  admit  the  water  to  the  pump:  since  it  is 
evident  that,  when  the  piston  or  plunger  commences  to  de- 
scend and  the  suction  valve  to  close,  the  water  passes  back 
through  the  suction  valve  until  it  is  closed,  thus  dimin- 
ishing the  effectiveness  of  the  pump,  and,  further,  causing 
the  valve  to  close  with  a  blow  which  proves  very  destruc- 
tive to  the  valves,  especially  of  fast-running  pumps. 

The  area  of  the  opening  of  a  suction  valve  must  be  at 
least  equal  to  the  area  of  the  suction  pipe,  whose  area  is 
determined  by  the  following  principles:  Water  will  not 


428  COMPLETE  PRACTICAL  MACHINIST. 

flow  through  a  suction  pipe  in  a  solid  stream  at  a  greater 
speed  than  that  of  500  feet  per  minute.  It  follows,  then, 
that,  the  quantity  of  water  the  pump  is  required  to  throw 
being  determined,  the  suction  pipe  must  be  of  such  a  size 
that  500  feet  of  it  will  hold  such  quantity. 

If  the  suction  pipe  be  any  smaller  than  that  size,  the 
pump  will  not  be  fully  supplied  with  water;  and  the  piston 
or  plunger  travelling  faster  than  the  supply  of  water  fol- 
lows it,  there  is,  when  it  arrives  at  the  end  of  its  suction 
stroke,  a  partial  vacuum  in  the  pump  barrel,  which  keeps 
the  suction  valve  open.  When  the  piston  or  plunger  has 
descended  until  it  strikes  the  water  again  (the  suction  valve 
not  having  yet  closed),  the  water,  descending  with  the 
piston,  strikes  the  suction  valve  with  a  blow,  which,  as  be- 
fore stated,  gives  a  backward  impetus  to  the  water  in  the 
suction  pipe,  and  closes  the  valve  with  a  blow  very  de- 
structive to  it;  especially  is  this  the  case  in  a  force  pump 
or  a  fast  running  steam  pump,  in  which  latter  case  the 
steam  piston  accelerates  in  speed  (when  the  pump  piston 
has  the  partial  vacuum  referred  to  in  it)  because  not  only 
is  the  steam  piston  relieved  from  performing  any  duty,  but 
it  is  assisted  by  the  vacuum  ;  so  that  it  accelerates  its  speed 
greatly  until  the  piston  strikes  the  water  in  the  pump 
barrel,  which  it  will  do  with  such  force  as  to  very 
probably  break  some  weak  part  of  the  engine  or  pump,  or 
cause  the  crossheads  or  piston  to  become  loose.  If  the 
working  parts  of  any  pump  are  accurately  fitted,  it  will 
deliver  more  nearly  its  full  capacity  of  water  when  run- 
ning slowly. 

An  air-chamber  placed  in  the  suction  side  of  any  pump 
causes  a  better  supply  of  water  to  the  pump  by  holding  a 
body  of  water  near  to  it,  and  by  making  the  supply  of 
water  up  the  suction  pipe  more  uniform  and  continuous. 
Air-chambers  should  be  made  as  long  in  the  neck  as  possi- 
ble or  convenient,  so  that  the  water,  in  passing  from  the 
pump  barrel  to  the  delivery  pipe,  shall  not  be  forced  up 


PUMPS.  429 

into  the  chamber  at  each  stroke  of  the  pump;  for  the  air 
in  the  chamber  becomes  gradually  absorbed  by  the  water. 
If  fresh  water  is  continually  passing  into  and  out  of  the 
chamber,  the  air  in  it  will  soon  become  absorbed,  and 
water  will  supply  its  place;  but  if  the  air-chamber  has 
a  long  neck,  the  water  at  its  highest  level  in  the  cham- 
ber will  remain  there  unchanged  by  the  action  of  the 
pump,  and  will  become  impregnated  with  air,  thus  di- 
minishing its  propensity  to  absorb  any  more;  and  al- 
though the  air  will  finally  become  all  absorbed  out  of  the 
air-chamber,  the  process  is  a  very  much  slower  one,  the 
air-chamber  being  so  much  the  more  effective,  and  its 
elasticity,  imparting  a  steady  flow  of  water  from  the  de- 
livery pipe,  being  unimpaired. 

Pumps  whose  pistons  revolve  are  subject  to  the  same 
defects  from  inequality  of  wear  as  are  rotary  engines,  but 
the  results  are  not  so  keenly  experienced,  because  water 
will  not  leak  through  so  rapidly  nor  to  so  serious  an  extent 
as  steam,  and,  further,  because  the  leakiness  of  the  pump 
may  be  compensated  for  by  an  increase  of  the  rotative 
speed  of  the  piston. 

Water  will  not,  however,  as  before  stated,  flow  through 
the  suction  pipe  at  a  greater  velocity  than  500  feet  per 
minute;  so  that,  if  the  pump  performs  more  revolutions 
than  are  requisite  (according  to  its  capacity)  to  carry  off 
more  than  the  quantity  of  water  contained  in  500  feet  of 
its  suction  pipe,  the  power  used  in  running  those  extra 
revolutions  is  lost,  inasmuch  as  they  are  superfluous  except 
for  the  purpose  of  compensating  for  the  defects  in  the  con- 
struction or  leakiness  of  the  pump,  in  which  case  the  excess 
of  speed  becomes  a  necessary  evil. 

In  actual  practice  it  is  found  that  the  efficiency  of  a 
pump  is  appreciably  increased  by  increasing  the  size  of 
suction  pipe  to  a  diameter  sufficiently  large,  that  the  water 
requires  to  travel  through  it  at  a  speed  of  not  more  than 
200  feet  per  minute.  It  is  also  found  that  the  effective- 


430  COMPLETE  PRACTICAL  MACHINIST. 

ness  of  a  pump  varies  with  the  height  it  draws  the  water, 
or  in  other  words,  the  length  of  the  suction  pipe. 

Prominent  among  the  causes  of  the  loss  of  efficiency  in 
pumps  appears  to  be  the  want  of  a  comparatively  large 
body  of  water  close  to  the  suction  side  of  the  pump.  Sup- 
posing a  single  acting  pump,  such  as  plunger  pumps  usually 
are,  to  have  a  suction  pipe  capable  of  supplying  as  much 
water  flowing  through  it,  at  a  speed  of  500  feet  per  minute, 
as  the  pump  delivers  per  minute.  In  the  first  place,  the 
water  only, flows  through  the  suction  pipe  at  and  during 
the  up  stroke,  so  that  the  water  will,  in  such  a  pump,  have 
to  pass  through  the  pipe  at  a  speed  equal  to  1000  feet  per 
minute.  So  that  the  suction  pipe  for  a  single  acting  pump 
should  be  of  such  a  size  that  it  will  deliver  as  much  .water 
flowing  through  it  at  a  speed  of  250  feet  per  minute,  as  the 
pump  delivers  per  minute,  in  which  case  the  water  in  the 
suction  pipe  will,  while  actually  in  motion,  move  at  a 
speed  of  500  feet  per  minute. 

If,  however,  the  pump  is  a  double  acting  one,  the  suc- 
tion pipe  may  be  of  such  size  that  it  will  deliver,  flowing 
through  it  at  a  speed  of  500  feet  per  minute,  as  much 
water  as  the  pump  will  deliver  per  minute,  or  in  other 
words,  the  suction  pips  should  bear  the  same  proportion 
in  size  to  a  single  acting  as  to  a  double  acting  pump. 

If  a  pump  makes  60  strokes  per  minute,  and  the  water 
flows  through  the  suction  pipe  at  the  rate  of  500  feet  per 
minute,  it  is  obvious  that  each  stroke  of  the  pump  will  draw 
the  water  from  a  length  of  over  8  feet  of  the  pipe.  Now  it 
is  a  good  pump  which  will  deliver  80  per  cent,  of  its  capa- 
city ;  allowing  a  loss  of  10  per  cent,  for  the  lift  and  fall  of 
the  valves,  we  still  have  a  loss  of  10  per  cent,  unaccounted 
for,  and  it  is  self-evident  that  the  column  of  water  enter- 
ing the  pump  must  be  broken  somewhere,  to  a  partial 
extent,  at  least,  and  it  is  reasonable  that  the  break  occurs 
close  to  the  pump,  because  the  water  close  to  the  pump  has 
not  the  friction  911  the  sides  of  the  pipe  tending  to  hold  it 


PUMPS.  431 

back.  Now,  if  a  pump  was  provided  with  a  reservoir 
(similar  to  a  steam  chest),  and  the  suction  valve  was  at 
the  bottom  of  such  reservoir,  there  would  be  very  little 
liability  of  the  pump  failing  to  get  a  full  supply  of  water, 
because  the  water  in  the  reservoir  would  flow  readily  into 
the  pump,  and  the  break,  if  any,  would  be  at  the  upper 
part  of  the  reservoir,  which  break  would,  provided  that 
the  suction  pipe  entered  the  reservoir  at  the  bottom,  cause 
a  continuous  flow  of  water  up  that  pipe,  while  at  the  same 
time  the  supply  to  the  pump  would  not  be  appreciably 
affected  by  the  break.  An  air-chamber  on  the  suction 
side  of  a  pump  does  not  fulfil  these  conditions,  because 
the  orifice  connecting  the  air-chamber  to  the  suction 
valve  is  comparatively  small,  whereas  the  whole  body  of 
water  in  the  proposed  reservoir  would  be  in  full  and  uncon- 
fined  communication  with  the  suction  orifice  or  port  of  the 
pump.  If  a  large  steam  chest  induces  an  initial  pressure, 
to  a  steam  cylinder,  more  approximate  to  that  obtaining  in 
the  boiler,  how  much  the  more  necessary  is  a  similar  chest 
or  reservoir  necessary  to  a  pump,  especially  when  it  is  con- 
sidered how  much  greater  is  the  inertia  oi  water  than  that 
ol  steam. 


INDEX. 


Adjustable  dies,  250,  251. 

Alloys,  237. 

American  chrome  steel  for  tools,  221, 222. 

Angle  of  top  and  bottom  faces  of  tools, 

39. 
Angles  of   threading    tools,  gauge    for 

testing,  90,  91,  92. 
Annealing  or  softening,  236. 
Arbors  or  mandrils,  120-122. 
Asbestos  for  joints,  313. 

Babbitt  metal  for  fast-running  journals, 
237. 

Babbitt  metal  bea'  ings,  wear  of,  235,  236. 

Bar  and  cutter,  168. 

Bars,  boring,  178-190. 

Bay  Chaleur  grindstones,  347. 

Bearings,  Babbitt  metal,  for  fast-running 
journals,  237. 

Bearings,  Babbitt  metal  or  of  brass,  wear 
of,  235,  230. 

Bearings,  cast-iron,  wear  of,  230. 

Hell  metal,  237. 

Bits  and  reamers,  71. 

Bits,  half-round,  IWi-lfiS. 

Blacksmith's  tools,  i-ffectof  blows  in  forg- 
ing, 238. 

Bolts  upon  targets  representing  ship's 
armor,  experiments  with,  94. 

Boring  bar,  conditions  necessary  in  a,  178. 

Boring  bar  cutters,  179. 

Boring  bar,  for  use  in  Itores  «  f  a  large 
diameter,  181. 

Boring  bar,  importance  of,  178. 

Boring  bar,  keyway  in,  180. 

Boring  bar,  the  position  wliich  the  cutter 
should  occupy  toward  the  head  of,  183- 
186. 

Boring  bars,  178-190. 

Boring  bars,  small,  18D,  190. 

Boring  light  brass  work,  79. 

Boring  links  or  levers,  144,  145. 

Boring  tool  for  brass.  78-81. 

Boring  tool  holders,  82,  83. 

Boring  tools  for  lathe  work,  71-83. 

Boring  tools  for  lathe  work,  shaping,  71. 

Boring  tools  for  wrought-iron,  cast-iron, 
steel  or  copper,  rake  of,  79. 

Boring  tools,  illustrations  of  the  various 
forms  of,  7fi,  77. 

Boult's  panelling  and  dovetailing  ma- 
chine, 210. 

Boxes,  fitting  brasses  to,  281,  285. 

Brass,  boring  tool  for,  78-81. 

37 


Brass  cutting,  speeds  and  feeds  for,  70. 
Brass  for  journal  boxes,  237. 
Brass  for  valves,  237. 
Brass  work,  boring,  79. 
Brass  work,  front  tool  for,  50-53, 
Brass  work,  grooving  tool  for,  45. 
Brass  work,  hand  turning,  159,  160. 
Brass  work,  roughing-out,  tool  for,  169, 

160. 

Brass  work,  scrapers  for,  160-163. 
Brass  work,  side  tool  for,  53,  54. 
Brass,  yellow,  237. 

Brasses,  fitting  to  their  boxes,  284,  285. 
Brasses,  letting  together  to  take  up  the 

wear,  323. 

Brasses,  lining  up  to  set  the  key,  324. 
Brasses  of  a  connecting  rod,  filing,  323. 
Browne  &  Sharpe  tap,  248,  249. 

Calculating  tho  speed  of  wheels,  pulleys, 
etc.,  411-413. 

Calipers,  90, 91, 264-267. 

Carrier  or  dog  for  lathe  work,  a  simple 
form  of,  116, 117. 

Case-hardening  wrought-iron,  229,  230. 

Cast-iron,  cutting  speeds  and  feeds  for, 
.70. 

Cast-iron  in  bearings  or  boxes,  wear  of, 
230. 

Cast-iron  piston  rings,  wear  of,  230. 

Cast-iron  slide  valves,  wear  of,  230. 

Cast-iron  under  steam  pressure,  wear  of, 
232. 

Cast-iron,  use  of  square-nosed  tools  on,  38. 

Cast-steel,  to  make  very  hard,  228. 

Centring  lathe  work,  122-127. 

Centring  machine,  124. 

Centre -drilling  attachment  for  lathe 
work,  124,  125. 

Centre-drilling  by  hand,  125,  126, 

Centre-drilling,  combined  drill  and  coun- 
tersink for,  124, 125. 

Change  gear  wheels  for  screws,  to  calcu- 
late, 91-102. 

Charcoal  for  heating  tools  in  hardening, 
226. 

Chaser,  outside,  for  cast-iron  or  brass, 
109,  110. 

Chaser,  outside,  for  cutting  wrought-iron, 
109, 110. 

Chaser,  to  make  a,  107-115. 

Chasers,  proportions  for,  108. 

Chasing,  hand,  104-107. 

Chisels,  256-261. 

(433) 


434 


INDEX. 


Chrome  steel  for  tools,  221,  2'22. 

Chrome  steel,  making  very  hard,  226. 

Chuck  a  crosshead,  to.  141-143. 

Chuck,  box-body,  131. 

Chuck,  dog,  135. 

Chuck,   expanding,  for   holding   piston 

rings,  149,  150. 

Chuck  of  the  Ku?sell  Tool  Co.,  134. 
Chuck,  the  Horton  two-jawed,  131. 
Chuck,  the  Sweetland,   133,  134. 
Chucking  an  eccentric,  136, 138, 139. 
Chucking  hand-turned  work,  153. 
Chucks,  lathe,  131-135. 
Chucks,  lathe,  division  of  into  classes, 

131. 

Chucks,  the  large  size  of,  131.  132. 
Chucks,  universal  or  scroll,  135. 
Clamp,  dog,  119. 
Clamps,  vise,  280,  281. 
Clearance  given  by  the  bottom  rake,  and 

the  side  rake  of  a  tool,  what  dependent 

on,  40. 

Clements'  driver  for  lathe  work,  116, 118. 
Cocks,  to  rivet  leaky  plugs  to,  304-308. 
Color  in  tempering  steel  for  tools,  222. 
Compound  or  double  screw-cutting  gear, 

97. 

Cone  pulley,  to  mark  out  a.  408-410. 
Connecting  rod,  lining  out,'  396  408. 
Connecting  rod  of  an  engine,  to  fit  a,  320. 
Connecting  rod,  to  get  the  length  of  a, 

319. 

Connecting  rods,  fitting,  314-324. 
Connecting  rods,  large,  forging,  300,  307. 
Copper,  cutting  speeds  and  feeds  for,  70. 
Counterbalancing  work,  14'3,  1 14. 
Countersink  drill,  a  taper,  212,  213. 
Countersink  drills,  212-214. 
Crank  of  a  horizontal  engine,  to  ascertain 

when  on  its  exact  dead  centre,  319. 
Cranks,  turning,  140. 
Crosshead,  to  chuck  a,  141-143. 
Crosshead,  to  mark  off  a,  381. 
Crosshead,  the  bores  of  a,  141. 
Cubical  block,  to  mark  a,  369-373. 
Curve  of  an    ellipse,  to  find  the  points 

through  which  it  may  be  drawn,  364. 
Cut.  hard  saw  blades,  to,  304, 
Cutter  and  bar,  168. 
Cutter  for  cutting  a  thread,  55. 
Cutter  stocks,  215. 
Cutters,  214-218. 
Cutters  and  milling  bar,  339-346. 
Cutters  are  steel  bits,  214. 
Cutters  of  boring  bars,  185, 186. 
Cutters,  recessing,  217,  218. 
Cutters,  tempering,  217,  218. 
Cutting  drifts,  326. 
Cutting  edge  in  round-nosed  tools,  36. 
Cutting  edge  of  a  tool,  height  of,  relation 

of  to  the  work,  40-42. 
Cutting  edge  of  a  tool,  pressure  on,  72. 
Cutting  edge  of  a  tool,  relation  of  the 

angle  to  which  it  stands  to  the  cut,  to 

the  pressure,  73,  74. 

Cutting  edge  of  a  tool,  the  principles  de- 
termining, 33-36. 
Cutting  edge  of  the  tools  of  Whitworth's 

lathes,  41. 


Cutting  edges  of  tools  should  be  as  near 

the  tool  post  as  possible,  41,  42. 
Cutting  edges  of  twist-drills,  197-200. 
Cutting  off  device,  59,  60. 
Cutting  off,  parting,  or  grooving  tools, 

44-47. 
Cutting  off  tool   holder,   and  steadying 

device,  59. 
Cutting  out  holes  of  a  large  diameter  in 

sheet-iron,  216,  217, 
Cutting  speed  and  feed,  64-70. 
Cutting  speeds  and  feeds  for  brass,  70. 
Cutting  speeds  and  feeds  for  cast-iron, 

70. 

Cutting  speeds  and  feeds  for  copper.  70. 
Cutting  speeds  and  feeds  for  steel,  C9. 
Cutting  speeds  and  feeds  for  wrought- 

iron,  69. 

Cutting  speeds  and  feeds,  tables  of.  69, 70. 
Cutting  surfaces  of  lathe  tools,  84. 
Cutting  tools,  conditions    affecting   the 

shape  of,  26. 
Cutting  tools,  effect  of  variation  of  shape 

or  presentment  of  the  work,  26. 
Cutting  tools  for  lathes  and  planing  ma- 
chines, 25-63. 

Cutting  tools  for  lather,  steel  for,'25. 
Cutting  tools  for  planing  machines,  42. 
Cutting  tools,  rake  of,  27-29. 
Cutting  tools,  steel  for,  219. 
Cutting  wedges,  machine  tools  are,  29. 
Cylinder  posts  and  steam  valves,  marking 

out,  406-408. 
Cylinders,  fitting,  288-297. 

Dead  centre  of  the  nank  of  a  horizontal 
engine,  to  asceitain  its  exact.  ol!». 

Diameter  of  work,  and  rake  of  a  tool,  re- 
lation of,  40. 

"l)iamond-poi?itcd  '  tool,  28. 

Dies,  adjustable,  250,  251. 

lies  and  taps,  238-255. 

Dies  for  use  in  hand  stocks,  251-255. 

Disc  surfaces,  revolving,  experiment  in 
regard  to  the  wear  of,  234. 

Distance  between  the  centres  of  two  hubs 
if  unequal  height,  379-381. 

Divide  a  straight  line  into  a  n  umber  of 
equidistant  points,  to,  :>(»7. 

Divide  a  straight  line  into  two  equal 
parts,  to,  367. 

Dog  or  carrier  for  lathe  work,  a  simple 
form  of,  116,  117. 

Dog,  the  clamp,  119. 

Dogs,  chuck,  135. 

Double  eye,  to  line  out  a,  383-389. 

Double  screwthread,  to  cut,  102-104. 

Drifts,  325-329. 

Drifts,  cutting,  326. 

Drift,  using  the,  327-329. 

Drill  and  countersink,  combined,  for  cen- 
tre-drilling, 125. 

Drill,  Farmer  lathe,  204. 

Drill,  flat,  for  enlarging  and  truing  out 
holes,  168-171. 

Drill  holder,  170,  171. 

Prill,  tit,  202. 

Drilling  hard  metals,  205,  206. 

Drilling  in  the  lathe,  164-171. 


INDEX. 


435 


Drills,  common,  used    as  countersinks. 

213. 

Drills,  countersink,  212-214. 
Drills,  feeding,  202-205. 
Drills,  flat,  201,  ?02. 
Drills,  flat,  defects  in,  20',  202. 
Drills  ground  by  hand,  testing  for  angle, 

199,  200. 

Drills,  machine  made,  shanks  of,  204. 
Drills,  pin,  211,212. 
Drills,  slotting  or  key  way,  206,  211. 
Drills,  temper  for,  204. 
Drills,  twist,  196-201. 
Driver  for  lathe  work,  Clements',  116, 

118. 

Hccentric,  chucking  an,  136-138. 
Kccentric,  marking  out  an,  389-396. 
Kccentrics,  turning,  136. 
Ellipse,  to  find  the  points  through  which 

the  curve  of  may  l>e  drawn,  364. 
Ellipse,  to  mark  out  an,  363,  364. 
Emery  cloth  and  paper,  128-130. 
Emery  wheel  for  grinding  reamers,  172. 
Emery  wheel,  use  of  with  milling  cutters, 

345,  346. 
Engine  guide  bar,  to  mark  out  an,  373- 

378. 

English  grindstones,  347. 
English  or  Whitworth  standard  for  screw 

threads,  244. 

English  standard  taps,  flutes  for,  246,  247. 
Examination   of  work  beibie  marking 

out,  369. 

Farmer  lathe  drill,  2  H. 

Feed  and  speed,  cutting.  64-70. 

Feeding  drills,  202-205 

Feeds  and  speeds,  culling,  tables  of,  69, 

70. 

File,  holding  a,  270. 
File,  selecting  a,  269. 
Files  and  filing,  269-280. 
Filing  out  templates.  272-280. 
Finishing  lathe  work,  127,  128. 
Fitting  brasses  to  their  boxes,  284,  285. 
Fitting  connecting  rods.  314-324. 
Fitting  cylinders,  288-297. 
Fitting  link  motions,  285-288. 
Flanges,  fitting  to  boilers  or  flanges,  313. 
Flat  drill,  experiments  with,  204. 
Flat  drill  for  enlarging  and  truing  out 

holes,  168-171. 
Flat  drill,  grinding,  202. 
Flat  drill,  increasing  the  keenness  of  by 

means  of  an  ellipse,  202. 
Flat  drills,  201,202. 
Flute  of  a  tap,  spiral,  241. 
Flute  of  a  tap,  volute,  241. 
Flutes  for  small  taps,  243. 
Force  pumps,  425,  426. 
Forging  and  hardening  lathe  tools,  25. 
Forging  tools,  220-222. 
Four-flute  tap,  246,  247. 
Forms,  special,  of  lathe  tools,  54,  55. 
France,  pitches  of  threads  of  scivws  use 

in,  102. 
Franklin   Institute,  standard   for  screw 

threads  adopted  by,  243. 


Front  tool,"  2fi,  28. 
Front  tool  for  biass  work,  50-53. 

Ras  taps,  the  taper  of,  241,  242. 

Gauge  for  grinding  and  setting  screw 

tools,  92,  93. 

Gauge  for  testing  the  angles  for  thread- 
ing tools,  90.  91,  92. 

Gauze  joints  for  high  temperatures,  313. 
iirder.  wear  of,  232. 
5 rain  of  properly  forged  tool  steel,  226. 
Jraver,  the,  154-159. 
Graver,  the  application  of,  155-lnT. 
Grinding,  holding  a  tool  in,  352,  353. 
Grinding  pointed  tools.  355. 
Grinding  reamers,  172-174. 
Grindstone  and  tool  grinding,  347-359. 
Grindstone  for  engravers'  plates,  349. 
Grindstone  for  tool  grinding,  349. 
Grindstone  of  uneven  surface,  using  a, 

355. 
Grindstone,  the  face  of  a,  for  flnt  surfaces, 

352. 

Grindstone,  truing  device  for,  350,  351. 
Grindstones,  different  varieties  of,  and 

their  qualities,  347, 34*.. 
Grindstones,  fitting  with  traversing  rests, 

347. 

Grindstones  should  be  run  true,  349. 
Grindstones,  the  surfaces  of,  348. 
Grindstones,  use  of,  347. 
Grooving  tool,  61-63. 
Grooving  tool  for  brass  work,  45. 
Grooving  tool  for  wrought-iron  or  steel. 

44-46. 

Grooving  tools.  44-47. 
Gun  metal,  237. 

Half-round  bits,  166-168. 

Hand  chasing,  104-107. 

Hand  stocks,  dies  for  use  in,  251-255. 

Hand  taps,  248,  249. 

Hand  tools,  25. 

Hand  turning,  151-163. 

Hand  turning  brass  work,  159, 160. 

Hard  metals,  drilling,  205,  206. 

Hard  saw  blades,  to  cut,  304. 

Hardening,  227. 

Hardening  American  chrome  steel,  226. 

Hardening  and  tempering  tools,  222-227. 

Hardening  cast-steel,  228. 

Hardening  lathe  tools,  25. 

Hardening  springs,  227-229. 

Hardening  taps,  244-246. 

Hardness  in  tools,  sacrificing  by  over- 
heating. 225. 

Heat,  proper,  in  forging  taps,  238, 239. 

Heel  tool,  157-159. 

Heel  tool,  hardening,  158. 

Height  of  the  cutting  edge  of  a  tool,  re- 
lation of,  to  the  work,  40-42. 

Holders,  boring  tool,  82,  83 

Holders,  tools,  55-63. 

Holes,  to  enlarge,  and  true  out,  168. 

Horton  two-jawed  chuck  131 

Hubs  of  unequal  height,  to  i~iark  <-fl'  the 
distance  between  the  centres  of,  two, 
379-381. 

Huron  grindstones,  347. 


436 


INDEX. 


Independence  grindstones,  347. 

Iron  and  steel,   swelled  by  hardening, 

228. 

Tron,  case  hardening,  229,230. 
Iron,  side  tools  for,  47-50. 
Iron,  wrought  and  cast,  cutting  speeds 

and  feeds  for,  69,  70. 

Joint,  rust,  313. 

Joint,  steam  and  water,  313. 

Joint,  the  ground  or  scraped,  the  best. 

313. 

Joints,  gauze  for  high  temperature,  313. 
Joints  of  canvas  or  duck  coated  with  red 

lead,  313. 

Joints,  ordinary,  313. 
Joints,  red  lead,  313. 
Joints,  rubber,  313. 
Journal  boxes,  brass  for,  237. 
Journals,    fast-running,    Babbitt    metal 

for,  237. 

Keys,  reversed.  329-331. 
Key  way.  marking  out  a,  402. 
Keyway  or  slotting  drills,  206-211. 

Lathe  chucks,  131-135. 
Lathe-cutting  tools,  classification  of,  25. 
Lathe  dogs,  carriers  or  drivers,  116-119. 
Lathe,  hand  expert,  25. 
Lathe,  the  importance  of,  25. 
Lathe  tools,  cutting  surfaces  of,  84. 
Lathe  tools,  forging  and  hardening,  25. 
Lathe  tools,  special  forms  of,  54,  55. 
Lathe  work,  boring  tools  for,  71-83. 
Lathe  work,  centring,  122-127. 
Lathe  work,  feed  and  speed  in,  64,  65. 
Lathe  work,  finishing,  1^7,  128. 
Lathes  and  planing  machines,  cutting 

tools  for,  25-63. 
Leaky  plugs,  to  rivet  to  their  cocks,  304- 

308. 
Left  hand  thread,  wheels  necessary  to  cut, 

102. 

Lever  arms,  boring,  144,  145. 
Line,  a  straight,  to  divide  into  a  number 

of  equidistant  points,  3fi7. 
Line-shafting,  setting  in  line,  331-337. 
Line,  straight,  to  divide  into  two  equal 

parts,  367. 

Lining  or  marking  out  work,  360-410. 
Lining  or  marking  out  work,  tools  em- 
ployed in,  365,  366. 
Lining  out  a  double  eye,  383-339. 
Lining  out  connecting  rod,  390-408. 
Lining  out  work,  accuracy  required  in, 

361. 

Lining  out  work,  importance  of,  360. 
Lining  up  brasses,  324. 
Link  motions,  fitting,  285-288. 
Links  or  levers,  boring.  144,  145. 
Liverpool  grindstones,  347. 
Long  continuous  cuts,  tool  for,  33. 

Machine  steel,  hardening,  228. 
Machine  tools  are  cutting  wedges,  29. 
Machine  using  a  boring  bar  should  not 

stop,  while  the  finishing  cut  is  being 

taken,  180,  181. 


Mandrils  or  arbors,  120-122. 

Mark  off  the  distance  between  the  centres 

of  two  hubs  of  unequal  height,  to,  379- 

381. 

.Mark  out  an  ellipse,  363,  364. 
Marker  out,  qualifications  necessary  in 

a,  361-363. 
Marker  out,  tools  employed  by  the,  365, 

366. 

Marking  holes  at  a  right  angle,  381-383. 
Marking  off  a  crosshead,  381. 
Marking  or  lining  out  work,  360-410. 
Marking  out  a  cone  pulley,  408-410. 
Marking  out  a  cubical  block,  369-373. 
Marking  out  a  keyway,  402. 
Marking  out  an  eccentric,  389-396. 
Marking  out  an  engine  guide-bar,  373- 

378. 

Marking  out  a  rod  end,  397. 
Measuring  work  before  marking  out,  369. 
Mailing  grindstones,  347. 
Metals,  hard,  drilling,  205,  206. 
Metals  to  be  cut,  influence  of,  on  shape 

of  to.  1,26. 

Metal  surfaces,  wear  of.  230,  231. 
Milling  bar  and  cutters,  330-346. 
Milling  cutter,  339-316. 
Milling  cutters,  email  M/e,  344. 
Milling  machine,  imp'  rtance  of,  338. 
Milling  machines  and  milling  tools,  338- 

346. 

Milling  machines,  the  cutters  of,  64. 
Milling  tools  and  milling  machines,  M8- 

346. 

Mixture  of  metals,  237. 
Morse  Twist-diill  Co.,  thread  upon  Iho 


taps  of,  344. 
Mnsh 


et's  "special  tool  steel,"  220. 

New  Castle  grindstones.  347. 
Nova  Scotia  grindstones,  347. 

Oblong  holes,  drilling,  206. 

Ohio  grindstones.  347. 

Oil-hole  for  a  strap  for  a  connecting  or  a 

side  rod,  322. 
Overheating  tools  in  hardening,  225. 

Panelling    and     dovetailing     machine, 

Boult's,  210. 
Pening,  282-284. 
Pin    drill,   employing   as    flat-bottomed 

countersink  drill,  212. 
Pin  drills,  211,212. 
Pin  drills,  tempering,  211,  212. 
Pitch  of  screw,  a  coarse  tool  for  cutting, 

84,  85. 
Pitch  of  screws,  to  calculate  the  changed 

gear  wheels  for,  94-102. 
Piston,  boring,  to  ret  eive  the  piston  rod, 

145. 

Piston  pumps,  426-4.-H. 
Piston  ring,  expanding  chuck  fur  hold- 
inn,  150. 

Piston  rings,  cast-iron,  wear  of,  230. 
Piston  rings,  inside  diameter  or  bore  of, 

147. 

Piston  rings,  turning,  147. 
Pistons  nnd  rods,  turning,  H5,  146. 


INDEX. 


437 


Piston  rings,  1 40-150. 

Planer  tool,  a,  42,  43. 

Planing  machines,  cutting  speed  of,  64. 

Planing  machines,  cutting  tools  for,  25- 

63. 

Plug  tap,  241. 
Plugs,  leaky,  to  rivet  to  their  cocks,  304- 

308. 
Points  through  which  the  curve  of  an 

ellipse  may  be  drawn,  to  find,  364. 
Pratt  &  Whitney  tap,  248,  249. 
Principles  affecting  the  shape  of  cutting 

tools,  26,  27. 

Pulley,  cone,  to  mark  out  a,  4^8-410. 
Pulleys,   wheels,   etc.,  to  calculate   the 

speed  of,  411-413. 
Pumps,  423-4;H. 

Rake,  bottom  and  side  of  a  tool,  what  de- 
pendent on,  40. 
Rake,  effect  of  having  little  in  a  tool,  30, 

31. 

Rake,  front  and  side,  a  tool  with,  34,  35. 
Rake  front  in  a  tool,  effect  of,  34. 
Rake  in  cutting  tools,  27-29. 
Rake  of  a  tool,  and  diameter  of  work, 

relation  of,  40. 

Rake,  side  and  front,  in  a  tool,  33. 
Rake,  side,  in  a  tool,  31-3:3. 
Rake,  side,  in  a  to  >1,  effect  of,  34. 
Rake,  top,  effect  of  a  great,  in  a  tool,  29, 

30. 

Rake,  top,  in  a  tool,  35. 
Rake,  top,  in  a  tool,  effect  of,  31. 
Reamer,  adjustable,  for  small  work,  175, 

176,  177. 
Reamer,  considerations  in   determining 

the  form  of,  171,  172 
Reamer,  method  of  grinding.  172-174. 
Reamer,  standard,   great  advantage  of, 

174. 
Reamer,  the,  to  maintain    to  standard 

diameter,  174. 
Reamers,  171-177. 

Reamers,  adjustable,  174,  175,  176, 177. 
Reamers  and  bits,  171. 
Reamers,  shell,  176, 177. 
Re-centring   work    which    has    already 

been  turned,  126,127. 
Reciprocating    and    revolving    surfaces, 

wear  in,  234,  235. 
Red  lead  joints,  313. 
Reversed  keys,  329-331. 
Riveting  work  by  shrinking  it,  308-312. 
Rivet  leaky  plugs  to  their  cocks,  to,  304- 

308. 

Rod  end,  marking  out  a,  397. 
Rotary  engines,  difficulty  of  the  success 

of,  on  account  of  the  inequality  of  wear 

in  side  or  disc  surfaces,  233. 
Round-nosed  tools,  36,  37. 
Round-nosed  tools,  cutting  edge  on,  36. 
Rubber  joints,  313. 
Roughing-out  brass  work,  tool  for,  159. 

160. 

Roughing-out  hand-turned  work,  154. 
Ronghing-nut,  tool  for,  33. 
Russell  Tool  Co.'s  drill  chuck,  13 i. 
Rust  joint,  313. 

37* 


Saw  blades,  hard  to  cut,  304. 

Scale  in  hardened  steel,  226. 

Scraped  surfaces,  297-301. 

Scraper,  best  form  of,  301. 

Scrapers  and  scraping,  280,  281. 

Scrapers  for  brass  work,  160-163. 

Screw-cutting  gear,  compound  or  double, 
97. 

Screw-cutting  tools,  84-115. 

Screw  thread,  a  double,  to  cut,  102-104. 

Screw  threa/1,  the  United  States  standard, 
88,  89,  90. 

Screw  thread,  the  Whitworth,  88,  89. 

Screw  threads  in  use  in  the  United  States, 
the  shapes  of,  87-89. 

Screw  threads,  standards  for,  243,  244. 

Screw  threads  used  in  France,  pitches  of, 
102. 

Screw,  to  cut,  by  hand  in  the  lathe,  104- 
107. 

Screw  tools,  gauge  for  grinding  and  set- 
ting, P2. 

Screws,  to  calculate  the  clnngo  gear 
wheels  to  cut  the  pitch  of  threads  for, 
94-102. 

Scribing  block,  268. 

Sellers,  Wm.  &  Co.,  experiments  with  a 
flat  drill,  201. 

Setting  line  shafting  in  line,  331-337. 

Shafting,  line,  setting  in  line,  331-337. 

Shape  of  cutting  tools,  26. 

Shape  of  work,  importance  of,  in  harden- 
ing, 227. 

Shaping  machines,  tool  holders  for,  60-62. 

Sheet-iron,  cutting  out  holes  of  a  large 
diameter  in,  217. 

Shell  reamers,  176,  177. 

Shrinking,  riveting  work  by,  308-312. 

Side-rest  tools,  25. 

Side-rest  tools,  classification  of,  26. 

Side  tool,  26. 

Side  tool  for  brass  work,  53,  54. 

Side  tool  for  small  work,  48,  49. 

Side  tools  for  iron,  47-50. 

Side  tools,  left-handed  and  r'ght-handed, 
48. 

Sizing  die  for  finishing  taps,  242,  24:5. 

Skin  of  iron  or  brass  c;istings.  and  iron 
or  steel  forgings,  hardness  of,  342. 

Slide  valve,  considerations  in  setting, 
414. 

Slide  valve,  to  set  a,  414-422. 

Slide  valves,  cast-iron,  wear  of,  230. 

Slot  drill,  application  of  the  principles 
of  the  action  of,  210. 

Slotting  drill,  labor  saved  by,  210. 

Slotting  drills,  tempering,  209. 

Slotting  machine  tools,  191-195. 

Slotting  or  key  way  drills,  206-211. 

Soldering  liquid,  237. 

Solders,  237. 

Speed  and  feed,  cutting,  64-70. 

Speeds  and  feeds,  cutting,  tables  of,  69, 70. 

Speed  of  wheels,  pulleys,  etc.,  to  calcu- 
late, 411-413. 

Spring  tool,  26. 

Spring  tool,  for  finishing  sweeps,  curves, 
and  round  or  hollow  corners,  46! 

Spring  tool,  the  top  face  of  a,  47. 


438 


INDEX. 


Springs,  hardening,  227-229. 
Springs,  the  steel  for,  227,  223. 
Spur  centre,  the  wood-turners',  119, 120. 
Square-nosed  tool,  setting  and  feeding, 

38. 

Square-nosed  tools,  37-43. 
Square-nosed  tools,  what  used  upon,  37, 

38. 

Square,  the,  267. 
Steam  and  water  joints,  313. 
Steam  valves  and  cylinder  posts,  marking 

out,  406-408. 

Steadying  device  and  tool  holdor.  59. 
Steel,  cutting  speeds  and  feeds  for,  69. 
Steel  for  taps,  238. 
Steel,  grooving  tool  for,  44-46. 
Steel,  hardening  and  tempering,  222. 
Steel,  tool,  25,  219,  22(1. 
Stock  and  cutter,  in  cutting  out  holes  of 

a  large  diameter  in  sheet-iron,  216,  217. 
Straight  line,  to  divide,  into  two  equal 

parts,  267. 
Straight  line,  a.  to  divide  into  a  number 

of  equidistant  points,  367. 
Strain  on  a  tool,  29. 
Strain  upon  a  tool  in  cutting,  30. 
Straw  color  in  tempering  tools,  225. 
Suction  pumps,  423-425. 
Surface  plate,  to  make  a,  301-304. 
Surfaces,  scraped,  297-301. 
Sweetlaud  chuck,  the,  133, 134. 

Tables  of  cutting  speeds  and  feeds,  69,70. 

Tap,  a  three-flute,  246,  247. 

Tap,  finishing  tlie  thread  of,  by  passing 

through  a  sizing  die,  212,  243. 
Tap,  hand  and   m  >chine-made,  turning 

the  taper  of,  241,  242. 
Tap,  taper,  241 
Tap,  the  nut,  240. 
Tap,  the  plain  part  of  a,  242. 
Taper,  plug,  241. 
Taper  tap,  241. 
Taper  in  taps,  241,  242. 
Taper  tap,  the  proper  taper  for,  239. 
Taps  and  dies,  238-255. 
Taps  for  holes,  requiring,  to  be  exact  in 

diameter,  241. 

Taps  tor  holes  to  be  tapped  deeply,  242. 
Taps  for  ordinary  work.  241. 
Taps  for  use  in   machines,  threads  of, 

240,  241 . 

Taps,  forging,  238. 
Taps,  gas,  the  toper  of,  241,  242. 
Taps,  heating,  for  hardening,  244-246. 
Taps,  heating  in  f< Tging,  238. 
Taps,  small,  flute  for,  243. 
Taps,  standard,  screw  thread  for,  243,  244. 
Taps,  steel  for,  238. 
Taps,  taper  in  the  diameter  of  the  bottom 

of  the  thread,  241 . 
Taps,  threads  of,  239,  240. 
Taps,  threads  of,  finishing,  239. 
Taps,  three-fluted  and   four-fluted,  246, 

247,  248. 
Taps  with  thread  on  small  end  of  taper, 

242. 

Temper  for  drills,  204. 
Tempering  and  hardening  tools,  222-227. 


Tempering  a  tool  at  or  near  the  cutting 

edge  only,  223. 
Tempering  cutte'  s,  217,  218. 
Tempering  pin  drills,  211,  212. 
Tempering  slotting  drills,  209. 
Templates,  filing  out,  272-28  >. 
Thread,  internal  screw,  tool  for  cutting, 

87. 
Thread,  left-hand,  wheels   necessary   to 

out,  102. 
Threading  tools,  gauge  for  testing  the 

angles  of,  90,  91,  92. 
Threads  of   screws,  cutting    small  and 

thick,  84,  85. 

Threads  of  screws,  coarse,  cutting,  84, 85. 
Threads  of  screws  in  use  in  the  United 

States,  shapes  of,  87-89. 
Threads  of  taps,  239,  2W. 
Threads  of  taps,  finishing,  239. 
Threads  of  taps  of  small  size,  finishing, 

239. 
Threads  on  wrought-iron  or  steel,  tool 

for  cutting,  86. 
Threads,  outside  V,  in  brass  work,  to <>1  for 

cutting.  80. 

Threads,  V,  in  iron,  tool  for  cutting,  86. 
Tit  drill,  202. 
Tool  feed,  rake  of,  40. 
Tool  for  roughing  out  and  long-continu- 
ous cuts,  33. 

Tool  grinding  and  grindstone,  347-359. 
Tool  hardening  and  tempering,  222-227. 
Tool  holder  and  steadying  device,  59. 
Tool  holder  for  planing  machine  tools, 

61-63. 

Tool  holder,  Woodbridge's,  57-59. 
Tool  holders,  55-63. 
Tool  holders  for  a  shaping  machine,  60- 

62. 

Tool  steel,  25,  219,  220. 
Tool  steel,  Mushet's,  220. 
Tool   with   a  combination  <  f  front  and 

side  rake,  34. 
Tools    and    tool   holders,   Woodbridge's, 

57-59. 

Tools,  angles  of,  39 
Tools,  cutting,  for   lathes  and  planing 

machines,  25-63. 
Tools  employed  by  the  marker  out,  365, 

366. 
Tools  for  cutting  various  screw  threads, 

80,  87. 

Tools,  forging,  220-222. 
Tools  for  use  in  slotting  machines,  classi- 
fication of,  181. 
Tools,  round-nosed,  36,  37. 
Tools,  screw-cutting,  84-115. 
Tools,  square-nosed,  37^13. 
Top  rake,  application  of,  to  a  boring  tool, 

relation  to  the  strain,  74,  75. 
Turning  cranks,  140. 
Turning  eccentrics,  136. 
Turning,  hand,  151-163. 
Turning  pistons  or  rods,  145,  146. 
Twist-drills,  196-201. 
Twist-drills,  cutting  edges  of,  197-200. 

United  States  standard  for  screw  threads, 
243. 


INDEX. 


'-39 


United  States  standard  screw  thread,  88, 

89,  90. 
United  States,  the  screw  threads  in  use 

in,  87-89. 

Valves,  brass  for,  237. 
Vise  clamps,  280,  281. 
Vise  work,  256-313. 

Water  and  ste'im  joints,  313. 

Wear  arising  from  motion  in  one  contin- 
uous direction,  230. 

Wear  greater  in  revolving  than  in  recip- 
rocating surfaces,  234,  235. 

Wear,  inequality  of,  in  revolving  side  or 
disc  surfaces,  233. 

Wear  of  metsil  surfaces,  230-230. 

Wheels,  pulleys,  etc.,  to  calculate  the 
speed  of,  411-413. 


Whitworth  or  English  standard  for  screw 

thread,  244. 
Whitworth   or    English    standard    tapj,_ 

flutes  for,  246,  247. 
Whitworth  screw  thread,  88,  89. 
Whitwoi  th,  Sir  Joseph,  lathes  of,  41. 
Whitworth  stocks  and  dies,  253. 
Whitwoi  th  taps,  flutes  and  teeth,  218, 249. 
Wickersly  grindstones,  347. 
Woodbridge's  patent  tool  and  tool  holder, 

57-59. 

Wrought-iron,  case-hardening,  229,  230. 
Wrought- iron,  cutting  speeds  and  feeds, 

69. 

Wrought-iron,  grooving  tool  for,  44-46. 
Wrought-iron,  screw-cutting  tools  for,  84. 

Yellow  brass,  237. 

Yellow  brass  for  castings,  237. 


Joshua  Rose,  M.  E., 

P.  O.  Box  3306,  New  York  City, 

Author  of l '  The  Complete  Practical  Machinist, "  ' '  The  Pat- 
tern Maker1  s  Assistant"  "The  Slide  Valve"  "Me- 
chanical Drawing  Self- Taught"    "Modern 
Machine  Shop  Practice. ' ' 

Gives  mechanical  advice  upon 
The  purchase  of  Machine  Tools, 

The  selection  of  Machinery, 

The  fitting  out  of  Workshops, 

The  value  of  Inventions, 

and  prepares  Catalogues  and  Descriptions  of  Machin- 
ery and  of  New  Inventions. 

The  Sweetland  Chuck 

Universal  and  Independent. 
A  first-class  tool  thoroughly  well  made. 


SWEETLAND  &  CO.,  NEW  HAVEN,  CONNECTICUT. 


The  Russell  Tool  Co.'s 

DRILL  CHUCK 


Will  drive  work  to  be  turned 
without  any  slip,  without  the 
use  of  a  wrench,  and  with- 
out being  strained, 


Operates  easily,  is  thoroughly 
well  made, 


Jaws  of  best  hardened  steel, 


Warranted  to  give  satisfaction 
and  be  durable, 


THE  RUSSELL  TOOL  CO., 


96^  Summer  Street. 


Boston,  Mass. 


F.  E.  REED, 

Manufacturer  of 

Light  Machinists'  Tools, 


54  Hermon  Street,        Worcester,  Mass., 

TJ.  S.  .A.. 


FOOT  POWER  LATHES  A  SPECIALTY. 


OF 


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BOOTH  and  MORFIT. — The  Encyclopaedia  of  Chemistry, 

Practical  and  Theoretical : 

Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine  and  Pharmacy.  By  JAMES  C.  BOOTH,  Melter 
and  Refiner  in  the  United  States  Mint,  Professor  of  Applied  Chem- 
istry in  the  Franklin  Institute,  etc.,  assisted  by  CAMPBELL  MORFIT, 
author  of  "Chemical  Manipulations,"  etc.  Seventh  Edition.  Com- 
plete in  one  volume,  royal  8vo.,  978  pages,  with  numerous  wood-cuts 
and  other  illustrations  .  $5«oo 

BRAM  WELL.— The  Wool  Carder's  Vade-Mecum: 

A  Complete  Manual  of  the  Art  of  Carding  Textile  Fabrics.  By  W. 
C.  BRAMWELL.  Third  Edition,  revised  and  enlarged.  Illustrated. 
Pp.  400.  I2mo.  .  .  .  .  .  .  .  .  $2.50 

BRANNT.— A   Practical   Treatise  on  Animal  and  Vegetable 

Fats  and  Oils  : 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chemi- 
cal Properties  and  Uses,  the  Manner  of  Extracting  and  Refining 
them,  and  Practical  Rules  for  Testing  them ;  as  well  as  the  Manu- 
facture of  Artificial  Butter,  Lubricants,  including  Mineral  Lubricating 
Oils,  etc.,  and  on  Ozokerite.  Edited  chiefly  from  the  German  of 
DRS.  KARL  SCHAEDLER,  G.  W.  ASKINSON,  and  RICHARD  BRUNNER, 
with  Additions  and  Lists  of  American  Patents  relating  to  the  Extrac- 
tion, Rendering,  Refining,  Decomposing,  and  Bleaching  of  Fats  and 
Oils.  By  WILLIAM  T.  BRANNT.  Illustrated  by  244  engravings. 
739  pages.  8vo.  ........  $7.50 

BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science; 
comprising  the  Chemistry,  Raw  Materials,  Machinery,  and  Utensils 
and  Various  Processes  of  Manufacture.  Edited  from  the  German  of 
Dr.  C.  DEITE,  A.  ENGELHARDT,  Dr.  C.  SCHAEDLER,  and  others. 
By  WILLIAM  T.  BRANNT.  Illustrated  by  numerous  Engravings.  8vo. 
(In  Preparation.) $ 

BRANNT.— A  Practical  Treatise  on  the  Raw  Materials  and  the 
Distillation  and  Rectification  of  Alcohol,  and  the  Prepara- 
tion of  Alcoholic  Liquors,  Liqueurs,  Cordials,  Bitters,  etc.  : 
Edited  chiefly  from  the  German  of  Dr.  K.  Stammer,  l)r.  F.  Eisner, 
and  E.  Schubert.     By  WM.  T.  BRANNT.     Illustrated  by  thirty-one 
engravings.     121110 $2.50 


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BRANNT— WAHL.— The  Techno-Chemical  Receipt  Book: 

Containing  several  thousand  Receipts  covering  the  latest,  most  im 
portant,  and  most  useful  discoveries  in  Chemical  Technology,  an<J 
their  Practical  Application  in  the  Arts  and  the  Industries.  Editea 
chiefly  from  the  German  of  Drs.  Winckler,  Eisner,  Heintze,  Mier- 
zinski,  Jacobsen,  Roller,  and  Heinzerling,  with  additions  by  WM.  T. 
BRANNT  and  WM.  H.  WAHL,  PH.  D.  Illustrated  by  78  engravings. 
I2mo.  495  pages  .  .  .....  $2.00 

BROWN.— Five  Hundred  and  Seven  Mechanical  Movements: 
Embracing  all  those  which  are  most  important  in  Dynamics,  Hy- 
draulics, Hydrostatics,  Pneumatics,  Steam-Engines,  Mill  and  other 
Gearing,  Presses,  Horology  and  Miscellaneous  Machinery;  and  in- 
cluding many  movements  never  before  published,  and  several  of 
which  have  only  recently  come  into  use.  By  HENRY  T.  BROWN. 
I2mo.  . $i.oc 

BUCKMASTER.— The  Elements  of  Mechanical  Physics  : 
By  J.  C.  BUCKMASTER.       Illustrated   with    numerous   engravings. 
I2mo. .$1.50 

BULLOCK. — The  American  Cottage  Builder  : 

A  Series  of  Designs,  Plans  and  Specifications,  from  $200  to  $20,000, 
for  Homes  for  the  People ;  together  with  Wanning,  Ventilation, 
Drainage,  Painting  and  Landscape  Gardening.  By  JOHN  BULLOCK, 
Architect  and  Editor  of  "  The  Rudiments  of  Architecture  and 
Building,"  etc.,  etc.  Illustrated  by  75  engravings.  8vo.  $3.50 

BULLOCK. — The  Rudiments  of  Architecture  and  Building : 
For  the  use  of  Architects,   Builders,   Draughtsmen,   Machinists,  En- 
gineers and  Mechanics.     Edited  by  JOHN  BULLOCK,  author  of  "  The 
American  Cottage  Builder."   Illustrated  by  250  Engravings.  8vo.  $3.50 

BURGH. — Practical    Rules    for    the   Proportions   of     Modern 

Engines  and  Boilers  for  Land  and  Marine  Purposes. 
By  N.  P.  BURGH,  Engineer.     I2mo.      ..  .  ;    • -,-       •»        .        $1.50 

BYLES. — Sophisms    of     Free    Trade    and    Popular    Political 

Economy  Examined. 

By  a  BARRISTER  (SiR  JOHN  BARNARD  BYLES,  Judge  of  Common 
Pleas).  From  the  Ninth  English  Edition,  as  published  by  the 
Manchester  Reciprocity  Association.  12010.  .  .  ..  ,  .  $1.25 

BOWMAN. — The  Structure  of  the  Wool  Fibre  in  its  Relation 

to  the  Use  of  Wool  for  Technical  Purposes  : 
Being  the  substance,  with  additions,  of  Five  Lectures,  delivered  at 
the  request  of  the  Council,  to  the  members  of  the  Bradford  Technical 
College,  and  the  Society  of  Dyers  and  Colorists.  By  F.  H.  Bow- 
MAN,  D.Sc.,  F.R.  S.  E.t  F.  L.  S.  Illustrated  by  32  engravings. 
8vo $6.50 

BYRNE. — Hand-Book  for  the  Artisan,  Mechanic,  and  Engi- 
neer: 

Comprising  the  Grinding  and  Shnrpening  of  Cutting  Tools,  Abrasive 
Processes,  Lapidary  Work,  Gem  and  Glass  Engraving,  Varnishing 
and  Lackering,  Apparatus,  Materials  and  Processes  for  Grinding  and 


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Polishing,  etc.  By  OLIVER  BYRNE.  Illustrated  by  185  wood  en- 
gravings. 8vo.  ........  $5.00 

BYRNE. — Pocket-Book  for  Railroad  and  Civil  Engineers : 
Containing  New,  Exact  and  Concise  Methods  for  Laying  out  Railroad 
Curves,  Switches,  Frog  Angles  and  Crossings ;  the  Staking  out  of 
work;  Levelling;  the  Calculation  of  Cuttings;  Embankments;  Earth- 
work, etc.  By  OLIVER  BYRNE.  i8mo.,  full  bound,  pocket-book 
form $1-75 

BYRNE. — The  Practical  Metal- Worker's  Assistant : 

Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all  Metals 
and  Alloys;  Forging  of  Iron  and  Steel;  Hardening  and  Tempering; 
Melting  and  Mixing;  Casting  and  Founding;  Works  in  Sheet  Metal; 
the  Processes  Dependent  on  the  Ductility  of  the  Metals;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal- 
workers. With  the  Application  of  the  Art  of  Electro-Metallurgy  to 
Manufacturing  Processes ;  collected  from  Original  Sources,  and  from 
the  works  of  Holtzapffel,  Bergeron,  Leupold,  Plumier,  Napier, 
Scoffern,  Clay,  Fairbairn  and  others.  By  OLIVER  BYRNE.  A  new, 
revised  and  improved  edition,  to  which  is  added  an  Appendix,  con- 
taining The  Manufacture  of  Russian  Sheet-Iron.  By  JOHN  PERCY, 
M.  D.,  F.  R.  S.  "The  Manufacture  of  Malleable  Iron  Castings,  and 
Improvements  in  Bessemer  Steel.  By  A.  A.  FESQUET,  Chemist  and 
Engineer.  With  over  Six  Hundred  Engravings,  Illustrating  every 
Branch  of  the  Subject.  8vo $7.00 

HYRNE.— The  Practical  Model  Calculator: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work,  Navai 
Architect,  Miner  and  Millwright.  By  OLIVER  BYRNE.  8vo.,  nearly 
600  pages #4.5$ 

CABINET  MAKER'S  ALBUM  OF  FURNITURE: 

Comprising  a  Collection  of  Designs  for  various  Styles  of  Furniture. 
Illustrated  by  Forty-eight  Large  and  Beautifully  Engraved  Plates. 
Oblong,  8vo.  .........  $3.50 

CALLINGHAM. — Sign  Writing  and  Glass  Embossing: 

A  Complete  Practical  Illustrated  Manual  of  the  Art.  By  JAMES 
CALLINGHAM.  i2mo #1.50 

CAMPIN. — A  Practical  Treatise  on  Mechanical  Engineering: 
Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools,  Work, 
shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam- 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Iron 
Ores.  By  FRANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention ;  with  a  Chapter  on  Explosions.  By  R. 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  Rules  for  Calculating  th« 
Change  Wheels  for  Screws  on  a  Turning  Lathe,  and  for  a  Wheel- 
cutting  Machine.  By  J.  LA  NICCA.  Management  of  Steel,  Includ- 
ing Forging,  Hardening,  Tempering,  Annealing,  Shrinking  and 
Expansi  >n  ;  and  the  Case-hardening  of  Iron.  By  G.  EDE.  8vo. 
Illustrated  with  twenty-nine  plates  and  100  wood  engravings  $5.00 


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CAREY. — A  Memoir  of  Henry  C.  Carey. 

By  DR.  WM.  ELDER,    With  a  portrait.     8vo.,  cloth        .         .        75 

CAREY.— The  Works  of  Henry  C.  Carey : 

Harmony  of  Interests  :    Agricultural,  Manufacturing  and  Commer* 
cial.     8vo.  .....  .         .         $1.50 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  I  vol.  I2mo.  .  $2.25 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  $6.00 

Past,  Present  and  Future.     8vo -»        $2.50 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  $10.00 
The  Slave-Trade,  Domestic  and  Foreign;  Why  it  Exists,  and 
How  it  may  be  Extinguished  (1853).  8vo.  .  .  .  $2.00 
The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental  and  Moral  Science  (1872).  8vo.  .  .  $3.50 

CLARK. — Tramways,  their  Construction  and  Working : 

Embracing  a  Comprehensive  History  of  the  System.  With  an  ex" 
haustive  analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air;  a  description  of  thr 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses. By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  2  vols.  8vo.  .  $12.50 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man- 
agement. By  ZERAH  COLBURN.  Illustrated.  i2mo.  .  $1.00 

COLLENS. — The  Eden  of  Labor;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"    "  The  History 
of  Charity,"  etc.     I2mo.     Paper  cover,  $  1. oo;  Cloth          .         $1.25 

COOLEY. — A  Complete  Practical  Treatise  on  Perfumery : 

Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Articles. 
With  a  Comprehensive  Collection  of  Formulae.  By  ARNOLD  J. 
COOLEY.  I2mo. $1.50 

COOPER.— A  Treatise  on  the  use  of  Belting  for  the  Trans- 
mission of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar- 
ranging Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten- 
ings. Examples  and  Rules  in  great  number  for  exhibiting  and  cal- 
culating the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Management  of 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  with 
chapters  on  the  Transmission  of  Power  by  Ropes ;  by  Iron  and 
Wood  Frictional  Gearing;  on  the  Strength  of  Belting  Leather;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  By 
JOHN  H.  COOPER,  M.  E.  8vo $3.50 

CRAIK. — The  Practical  American  Millwright  and  Miller. 

By  DAVID  CRAIK,  Millwright.  Illustrated  by  numerous  wood  en- 
gravings and  two  folding  plates.  8vo $5-OO 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  9 

CRISTIANI.— A  Technical  Treatise  on  Soap  and  Candles : 
With  a  Glance  at  the  Industry  of  Fats  and  Oils.     By  R.  S.  CRIS- 
TIANI, Chemist.     Author  of  "  Perfumery  and  Kindred  Arts."     Illus- 
trated by  176  engravings.     581  pages,  8vo.         .         .         .         $7-5° 
CRISTIANI.— Perfumery  and  Kindred  Arts: 

A  Comprehensive  Treatise  on  Perfumery,  containing  a  History  of 
Perfumes  from  the  remotest  ages  to  the  present  time.  A  complete 
detailed  description  of  the  various  Materials  and  Apparatus  used  in 

•  the  Perfumer's  Art,  with  thorough  Practical  Instruction  and  careful 
Formulae,  and  advice  for  the  fabrication  of  all  known  preparations  of 
the  day,  including  Essences,  Tinctures,  Extracts,  Spirits,  Waters, 
Vinegars,  Pomades,  Powders,  Paints,  Oils,  Emulsions,  Cosmetics, 
Infusions,  Pastilles,  Tooth  Powders  and  Washes,  Cachous,  Hair  Dyes, 
Sachets,  Essential  Oils,  Flavoring  Extracts,  etc. ;  and  full  details  for 
making  and  manipulating  Fancy  Toilet  Soaps,  Shaving  Creams,  etc., 
by  new  and  improved  methods.  With  an  Appendix  giving  hints  and 
advice  for  making  and  fermenting  Domestic  Wines,  Cordials,  Liquors, 
Candies,  Jellies,  Syrups,  Colors,  etc.,  and  'for  Perfuming  and  Flavor- 
ing Segars,  Snuff  and  Tobacco,  and  Miscellaneous  Receipts  for 
various  useful  Analogous  Articles.  By  R.  S.  CRISTIANI,  Con- 
sulting Chemist  and  Perfumer,  Philadelphia.  8vo.  .  .  #5'°° 

CUPPER.— The  Universal  Stair-Builder : 

Being  a  new  Treatise  on  the  Construction  of  Stair-Cases  and  Hand- 
Rails;  showing  Plans  of  the  various  forms  of  Stairs,  method  of 
Placing  the  Risers  in  the  Cylinders,  general  method  of  describing 
the  Face  Moulds  for  a  Hand-Rail,  and  an  expeditious  method  of 
Squaring  the  Rail.  Useful  also  to  Stonemasons  constructing  Stone 
Stairs  and  Hand-Rails  ;  with  a  new  method  of  Sawing  the  Twist 
Part  of  any  Hand-Rail  square  from  the  face  of  the  plank,  and  to  a 
parallel  width.  Also,  a  new  method  of  forming  the  Easings  of  the 
Rail  by  a  gauge ;  preceded  by  some  necessary  Problems  in  Practical 
Geometry,  with  the  Sections  of  Prismatic  Solids.  Illustrated  by  29 
plates.  By  R.  A.  CUPPER,  Architect,  author  of  "The  Practical 
Stair-Builder's  Guide."  Third  Edition.  Large  4to. 

DAVIDSON. — A  Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling,  and  Sign- Writing : 

Containing  full  information  on  the  processes  of  House  Painting  in 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Principles  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  With  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A.  DAVIDSON.  I2mo. 

$3.00 

CAVIES. — A   Treatise   on    Earthy  and   Other   Minerals    and 

Mining : 

By  D.  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  etc.  Illustrated  by 
76  Engravings.  I2mo $5.00 


ro          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

DAVIES.— A  Treatise  on  Metalliferous  Minerals  and  Mining: 
By  D.  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  Examiner  of  Mines, 
Quarries  and  Collieries.    Illustrated  by  148  engravings  of  Geological 
Formations,    Mining   Operations   and   Machinery,   drawn   from    the 
practice  of  all  parts  of  the  world.    2d  Edition,  I2mo.,  450  pages  $5.00 

DAVIES. — A  Treatise  on  Slate  and  Slate  Quarrying: 
Scientific,  Practical  and  Commercial.     By  D.  C.  DAVIES,  F.  G.  S., 
Mining   Engineer,  etc.     With    numerous    illustrations   and    folding 
plates.     I2mo.          .         .         .         .         .         .       '..      .-•          $2.50 

DAVIS. — A  Practical  Treatise  on  the  Manufacture  of  Bricks, 
Tiles,  Terra- Cotta,  etc. : 

Including  Common,  Pressed,  Ornamentally  Shaped,  and  Enamelled 
Bricks,  Drain-Tiles,  Straight   and  Curved   Sewer- Pipes,  Fire-Clays, 
Fire-Bricks,  Terra-Cotta,   Roofing-Tiles,  Flooring-Tiles,   Art-Tiles, 
Mosaic  Plates,  and  Imitation  of  Intarsia  or  Inlaid  Surfaces ;  com- 
prising every  important  Product  of  Clay  employed  in  Architecture, 
Engineering,  the  Blast-Furnace,  for  Retorts,  etc.,  with  a  History  and 
the  Actual   Processes  in   Handling,  Disintegrating,  Tempering,  and 
Moulding  the  Clay  into  Shape,   Drying   Naturally  and  Artificially, 
Setting  and  Burning,  Enamelling  in  Polychrome  Colors,  Composition 
and  Application  of  Glazes,  etc. ;  including  Full  Detailed  Descriptions 
of  the  most  modern  Machines,  Tools,  Kilns,  and  Kiln-Roofs  used. 
By  CHARLES  THOMAS  DAVIS.     Illustrated  by  228  Engravings  and 
6  Plates.     8vo.,  472  pages         ...          ....         $5.00 

DAVIS.— The  Manufacture  of  Leather: 

Being  a  description  of  all  of  the  Processes  for  the  Tanning,  Tawing, 
Currying,  Finishing  and  Dyeing  of  every  kind  of  Leather ;  including 
the  various  Raw  Materials  and   the  Methods  for  Determining  their 
Values;  the  Tools,   Machines,  and  all  Details  of  Importance  con- 
nected with  an  Intelligent  and  Profitable  Prosecution  of  the  Art,  with 
Special  Reference  to  the  Best  American   Practice.     To  which  are 
added  Complete  Lists  of  all  American  Patents  for  Materials,  Pro- 
cesses, Tools,  and  Machines  for  Tanning,  Currying,  etc.   By  CHARLES 
THOMAS  DAVIS.     Illustrated  by  302  engravings  and  12  Samples  of 
Dyed  Leathers.     One  vol.,  8vo.,  824  pages        .         .  $10.00 

DAWIDOWSKY— BRANNT.— A   Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilages, 
etc.: 

Eased  upon  Actual  Experience.     By  F.  DAWIDOWSKY,  Technical 
Chemist.     Translated  from  the  German,  with   extensive  additions, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM  T.  BRANNT,  Graduate  of  the  Royal  Agricultural  College 
of  Eldena,  Prussia.     35  Engravings.     I2mo.    .         .         .         $2.50 

DE  GRAFF.— The  Geometrical  Stair-Builders'  Guide : 

Being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  its 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Steel 
Engravings ;  together  with  the  use  of  the  most  approved  principles 
of  Practical  Geometry.  By  SIMON  DE  GRAFF,  Architect.  410. 

#2.50 


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DE  KONINCK— DIETZ.— A    Practical   Manual   of   Chemical 

Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DE 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.  S.  G.,  M.  I.  C.  E.,  etc.  American 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A. 
FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  .  $2.50 

DUNCAN.— Practical  Surveyor's  Guide:  t. 

Containing  the  necessary  information  to  make  any  person  of  com- 
mon capacity,  a  finished  land  surveyor  without  the  aid  of  a  teacher. 
By  ANDREW  DUNCAN.  Illustrated.  I2mo.  .  .  .  $1.2$ 

DUPLAIS.— A  Treatise  on  the  Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grnin,  Rice,  Potatoes,  Sorghum,  Aspho- 
del, Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy, 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aro- 
matic Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  the 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copious 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc.,  etc.  Translated  and  Edited  from  the  French  of  MM.  DUPLAIS, 
Aine  et  Jeune.  By  M.  McKENNiE,  M.  D.  To  which  are  added  the 
United  States  Internal  Revenue  Regulations  for  the  Assessment  and 
Collection  of  Taxes  on  Distilled  Spirits.  Illustrated  by  fourteen 
folding  plates  and  several  wood  engravings.  743  pp.  8vo.  $10  oo 

PUSSAUCE.— A   General    Treatise   on   the   Manufacture   of 

Vinegar: 

Theoretical  and  Practical.  Comprising  the  various  Methods,  by  the 
Slow  and  the  Quick  Processes,  with  Alcohol,  Wine,  Grain,  Malt, 
Cider,  Molasses,  and  Beets;  .is  well  as  the  Fabrication  of  Wood 
Vinegar,  etc.,  etc.  By  Prof.  H.  DUSSAUCE.  8vo.  .  $5  oo 

DUSSAUCE.— Practical  Treatise  on  the  Fabrication  of  Matches, 

Gun  Cotton,  and  Fulminating  Powder. 
By  Professor  H.  DUSSAUCE.     i2mo.          .         .         .         .         $3  oo 

DYER  AND  COLOR-MAKER'S  COMPANION: 

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EDWARDS. — A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practical  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty-three  Engravings,  including  examples  of 
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EDWARDS. — Modern  American  Locomotive  Engines, 
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12         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

EDWARDS. — Modern  American  Marine  Engines,  Boilers,  and 
Screw  Propellers, 

Their  Design  and  Construction.  Showing  the  Present  Practice  of 
the  most  Eminent  Engineers  and  Marine  Engine  Builders  in  the 
United  States.  Illustrated  by  30  large  and  elaborate  plates.  4to.  $5.00 

EDWARDS.— The  Practical  Steam  Engineer's  Guide 

In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam  Pumps,  Boilers,  Injectors, 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and  Steam 
Gauges.  For  the  use  of  Engineers,  Firemen,  and  Steam  Users.  By 
EMORY  EDWARDS.  Illustrated  by  119  engravings.  420  pages. 
I2mo $2  50 

ELDER.— Conversations  on  the  Principal  Subjects  of  Political 

Economy. 
By  Dr.  WILLIAM  ELDER.  8vo.         .        .        .        .  •"    .        $2  50 

ELDER. — Questions  of  the  Day, 

Economic  and  Social.     By  Dr.  WILLIAM  ELDER.  8vo.     .        $3  oo 

ELDER.— Memoir  of  Henry  C.  Carey. 

By  Dr.  WILLIAM  ELDER.  8vo.  cloth 75 

ERNI.— Mineralogy  Simplified. 

Easy  Methods  of  Determining  and  Classifying  Minerals,  including 
Ores,  by  means  of  the  Blowpipe,  and  by  Humid  Chemical  Analysis, 
based  on  Professor  von  Kobell's  Tables  for  the  Determination  of 
Minerals,  with  an  Introduction  to  Modern  Chemistry.  By  HENRY 
ERNI,  A.M.,  M.D.,  Professor  of  Chemistry.  Second  Edition,  rewritten, 
enlarged  and  improved.  I2mo.  .  .  .  .  <  $3  oo 

FAIRBAIRN.— The  Principles  of  Mechanism  and  Machinery 

of  Transmission  • 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pulleys, 
Strength  and  Proportions  of  Shafts,  Coupling  of  Shafts,  and  Engag- 
ing and  Disengaging  Gear.  By  SIR  WILLIAM  FAIRBAIRN,  Bait. 
C.  E.  Beautifully  illustrated  by  over  150  wood-cuts.  In  one 
volume,  I2mo  .  .  '  .  .  •*  •  •  •  #2.50 

FITCH.— Bessemer  Steel, 

Ores  and  Methods,  New  Facts  and  Statistics  Relating  to  the  .Types 
of  Machinery  in  Use,  the  Methods  in  Vogue,  Cost  and  Class  of  Labor 
employed,  and  the  Character  and  Availability  of  the  Ores  utilized  in 
the  Manufacture  of  Bessemer  Steel  in  Europe  and  in  the  United  States; 
together  with  opinions  and  excerpts  from  various  accepted  authorities. 
Compiled  and  arranged  by  THOMAS  W.  FITCH.  8vo.  .  $3  oo 

FLEMING. — Narrow  Gauge  Railways  in  America. 

A  Sketch  of  their  Rise,  Progress,  and  Success.  Valuable  Statistics 
as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  efc.  By 
HOWARD  FLEMING.  Illustrated,  8vo.  .  .  .  .  $i  50 

FORSYTH.— Book  of  Designs  for  Headstones,   Mural,   and 

other  Monuments : 

Containing  78  Designs.  By  JAMES  FORSYTH.  With  an  Introduction 
by  CHARLES  BOUTELL,  M.  A.  4  to.,  cloth  .  .  -  $5  oo 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          13 

FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu- 
facture of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine  : 

Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pest,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical! 
Manufacturer  of  Starch-Sugar.  Illustrated  by  58  engravings,  cover- 
ing every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  .  $3.50 

GEE.— The  Goldsmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting, and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste;  Chemical  and  Physical  Properties  of  Gofd;  with  a  New 
System  of  Mixing  its  Alloys;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  .  ..  $i-7S 

GEE. — The  Silversmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of -Refining  and  Melting  the  Metal;  its 
Solders  ;  the  Preparation  of  Imitation  Alloys ;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 
Memoranda.  By  GEORGE  E.  GEE,  Jeweller.  Illustrated.  I2mo. 

**.75 

GOTHIC  ALBUM  FOR  CABINET-MAKERS  : 

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GREEN  WOOD.— Steel  and  Iron : 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolling- 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN- 
WOOD, F.  C.  S.  Asso.  M.  I.  C.  E.,  M.  I.  M.  E.,  Associate  of  the  Royal 
School  of  Mines.  With  97  Diagrams,  536  pages.  I2mo.  .  $2.00 

GREGORY.— Mathematics  for  Practical  Men  : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  OLINTHUS  GREGORY.  %8vo.,  plates  .  $3.00 

GRIER.— Rural  Hydraulics : 

A  Practical  Treatise  on  Rural  Household  Water  Supply.  Giving  a 
full  description  of  Springs  and  Wells,  of  Pumps  and  Hydraulic  Ram, 
with  Instructions  in  Cistern  Building,  Laying  of  Pipes,  etc.  By  W. 
W.  GRIER.  Illustrated  8vo 75 

GRIMSH AW.— Modern  Milling: 

Being  the  substance  of  two  addresses  delivered  by  request,  at  the 
Franklin  Institute,  Philadelphia,  January  igih  and  January  27th, 
1881.  By  ROBERT  GRIMSHAW,  Ph.  D.  Edited  from  the  Phono- 
graphic Reports.  With  28  Illustrations.  8vo.  .  .  j&i.oo 

GRIMSHAW.— Saws : 

The  History,  Development,  Action,  Classification,  and  Comparison 
•"  ^AWS  of  all  kinds.  With  Copious  Appendices.  Giving  the  details 


14         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

of  Manufacture,  Filing,  Setting,  Gumming,  etc.  Care  and  Use  of 
Saws;  Tables  of  Gauges;  Capacities  of  Saw-Mills;  List  of  Saw- 
Patents,  and  other  valuable  information.  By  ROBERT  GRIMSHAW. 
Second  and  greatly  enlarged  edition,  with  Supplement,  and  354  Illus- 
trations. Quarto $4.00 

GRIMSHAW. — A  Supplement  to  Grimshaw  on  Saws: 

"  Containing  additional  practical  matter,  more  especially  relating  to  the 
Forms  of  Saw-Teeth,  for  special  material  and  conditions,  and  to  the 
Behavior  of  Saws  under  particular  conditions.  120  Illustrations.  By 
ROBERT  GRIMSHAW.  Quarto  .  .  .  .  .  $2.00 

GRISWOLD. — Railroad  Engineer's  Pocket  Companion  for  the 

Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En- 
gineers; also  the  Art  of  Levelling  from  Preliminary  Survey  to  the 
Construction  of  Railroads,  intended  Expressly  for  the  Young  En- 
gineer, together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  I2mo.,  tucks  .  .  . ''.'•'*  '•'-  .  $1-7$ 

GRUNER.— Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  of 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  author's  sanction,  with  an  Appendix,  by  L.  D. 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

GUETTIER.— Metallic  Alloys : 

Being  a  Practical  Guide  to  their  Chemical  and  Physical  Properties, 
their  Preparation,  Composition,  and  Uses.  Translated  from  the 
French  of  A.  GUETTIER,  Engineer  and  Director  of  Founderies, 
author  of  "  La  Fouderie  en  France,"  etc.,  etc.  By  A.  A.  FESQUET, 
Chemist  and  Engineer.  I2mo. $3.00 

HASERICK. — The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleaching  and  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yarns 
or  Fabrics.  8vo.  .,•-.- $25.oC 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  Hatter. 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  $1.25 

HENRY.— The  Early  and  Later  History  of  Petroleum : 

With  Authentic  Facts  in  regard  to  its  Development  in  Western  Penn- 
sylvania. With  Sketches  of  the  Pioneer  and  Prominent  Operators, 
together  with  the  Refining  Capacity  of  the  United  States.  By  J.  T. 
HENRY.  Illustrated  8vo. 

HOFFER. — A   Practical   Treatise   on   Caoutchouc  and   Gutta 

Percha, 

Comprising  the  Properties  of  the  Raw  Materials,  and  the  manner  of 
Mixing  and  Working  them ;  with  the  Fabrication  of  Vulcanized  and 
Hard  Rubbers,  Caoutchouc  and  Gutta  Pescha  Compositions,  Water* 


HENRY  CAREY  BAIRD  £  CO.'S  CATALOGUE.          15 

proof  Substances,  Elastic  Tissues,  the  Utilization  of  Waste,  etc.,  etc. 
From  the  German  of  RAIMUND  HOFFER.  By  W.  T.  ERANNT. 
Illustrated  I2mo $2.50 

HOFMANN.— A   Practical   Treatise  on   the   Manufacture  of 

Paper  in  all  its  Branches  : 

By  CARL  HOFMANN,  Late  Superintendent  of  Paper-Mills  in  Germany 
and  the  United  States ;  recently  Manager  of  the  "  Public  Ledger " 
Paper-Mills,  near  Elkton,  Maryland.  Illustrated  by  no  wood  en- 
gravings, and  five  large  Folding  Plates.  4to.,  cloth;  about  400 
pages $35-°° 

HUGHES.— American  Miller  and  Millwright's  Assistant: 
By  WILLIAM  CARTER  HUGHES.    i2mo $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing  : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich; the  Royal  Military  College,  Sandhurst;  the  Indian  Civil  En- 
gineering College,  Cooper's  Hill ;  Indian  Public  Works  and  Tele- 
graph Departments ;  Royal  Marine  Light  Infantry  ;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 
examples.  Small  quarto $3-75 

JERVIS.— Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property ;  as  well  as  Railway  Managers,  Offi- 
cers, and  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  the 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  $2.00 

KEENE. — A  Hand-Book  of  Practical  Gauging: 

For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla* 
tion,  describing  the  process  in  operation  at  the  Custom-House  for 
ascertaining  the  Strength  of  Wines.  By  JAMES  B.  KEENE,  of  H.  M. 
Customs.  8vo.  ........  $1.25 

KELLEY.— Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 
By  HON.  WILLIAM  D.  KELLEY,  M.  C.     544  pages,  8vo.  .        $3.00 

KELLOGG. — A  New  Monetary  System  : 

The  only  means  of  Securing  the  respective  Rights  of  Labor  and 
Property,  and  of  Protecting  the  Public  from  Financial  Revulsions. 
By  EDWARD  KELLOGG.  Revised  from  his  work  on  "  Labor  and 
other  Capital."  With  numerous  additions  from  his  mnnuscript. 
Edited  by  MARY  KELLOGG  PUTNAM.  Fifth  edition.  To  which  is 
added  a  Biographical  Sketch  of  the  Author.  One  volume,  I2mo. 

Paper  cover $l.oo 

Bound  in  cloth 1.50 

KEMLO.— Watch-Repairer's  Hand-Book : 
Being  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apart, 
Putting  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  Foreign  Watches,  and  all  American  Watches.     By  F.  KEMLO, 
Practical  W^urr~ker.     With  Illustrations.     I2mo.  .        $1.25 


16          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

KENTISH. — A  Treatise  on  a  Box  of  Instruments, 

And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Loga- 
rithms, including  Practical  Geometry,  Surveying,  Measuring  of  Tim. 
her,  Cask  and  Malt  Gauging,  Heights,  and  Distances.     By  THOMAS 
KENTISH.     In  one  volume.     I2mo.    .        .      '.      ~ ,-        .        $1.2$ 
KERL.— The  Assayer's  Manual : 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.     By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines;    Member  of  the   Royal   Technical 
Commission  for  the  Industries,  and  of  the   Imperial  Patent-Office, 
Berlin.     Translated  from  the   German   by  WILLIAM   T.   BRANNT, 
Graduate    of  the    Royal    Agricultural   College   of   Eldena,    Prussia. 
Edited  by  WILLIAM  H.  WAHL,  Ph.  D.,  Secretary  of  the  Franklin 
Institute,  Philadelphia.     Illustrated  by  sixty-five  engravings.    8vo. 

$3-00 
KINGZETT. — The   History,  Products,  and   Processes  of  the 

Alkali  Trade : 

Including  the  most  Recent  Improvements.     By  CHARLES  THOMAS 
KINGZETT,  Consulting  Chemist.    With  23  illustrations.    8vo.       $2.50 
KINSLEY.— Self-Instructor  on  Lumber  Surveying: 

For  the  Use  of  Lumber   Manufacturers,  Surveyors,  and  Teachers. 
By  CHARLES  KINSLEY,  Practical  Surveyor  and  Teacher  of  Surveying. 
I2mo.        .:       .....         .         .         »         .         $2.00 

KIRK.— The  Founding  of  Metals : 

A  Practical  Treatise  on  the  Melting  of  Iron,  with  a  Description  of  the 
Founding  of  Alloys;  also,  of  all  the  Metals  and  Mineral  Substances 
used  in  the  Art  of  Founding.  Collected  from  original  sources.  By 
EDWARD  KIRK,  Practical  Foundryman  and  Chemist.  Illustrated. 

Third  edition.     8vo. $2.50 

KITTREDGE. — The    Compendium    of    Architectural    Sheet- 
Metal  Work : 

Profusely  Illustrated.  Embracing  Rules  and  Directions  for  Estimates, 
Items  of  Cost,  Nomenclature,  Tables  of  Brackets,  Modillions,  Den- 
tals,  Trusses,  Stop-Blocks,  Frieze  Pieces,  etc.  Architect's  Specifica- 
tion, Tables  of  Tin-Roofing,  Galvanized  Iron,  etc.,  etc.  .To  which  is 
added  the  Exemplar  of  Architectural  Sheet-Metal  Work,  containing 
details  of  the  Centennial  Buildings,  and  other  important  Sheet-Metal 
Work,  Designs  and  Prices  of  Architectural  Ornaments,  as  manufac- 
tured for  the  Trade  by  the  Kittredge  Cornice  and  Ornnment  Com- 
pany, and  a  Catalogue  of  Cornices,  Window-Caps,  Mouldings, etc.,  as 
manufactured  by  the  Kittredge  Cornice  and  Ornament  Company. 
The  whole  supplemented  by  a  full  Index  and  Table  of  Contents.  By 
A.  O.  KITTREDGE.  8vo.,  565  pages  .  .  ... 
LANDRIN.— A  Treatise  on  Steel : 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.,  Civil  Engineer.  Translated 
from  the  French,  with  Notes,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer.  With  an  Appendix  on  the  Bessemer  and  the  Martin  Pro- 
far  Manufacturing  Steel,  from  the  Report  of  Abram  S.  H«witt 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          17 

United  States  Commissioner  to  the  Universal  Exposition,  Paris,  1867. 

I2mo.  .  •  . $3-oo 

LARDEN. — A  School  Course  on  Heat: 

By  W.  LARDEN,  M.  A.  321  pp.  I2mo.  .  .  .  $2.00 

LARDNER. — The  Steam -Engine: 

For  the  Use  of  Beginners.    By  DR.  LARDNER.    Illustrated.    I2mo. 

fcARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide: 

A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  and 
their  Alloys,  etc.;  to  which  are  added  Recent  Improvements  in  the 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  By 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  in 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  Fifth  edition, 
revised,  with  extensive  additions.  I2mo.  .  .  .  $2.25 

LEROUX.— A    Practical     Treatise     on    the    Manufacture    of 

Worsteds  and  Carded  Yarns  : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  the 
International  Jury,  and  of  the  Artisans  selected  by  the  Committee 
appointed  by  the  Council  of  the  Society  of  Arts,  London,  on  Woolen 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni- 
versal Exposition,  1867.  8vo.  .....  $5.00 

LEFFEL. — The  Construction  of  Mill-Dams  : 
Comprising  also  the  Building  of  Race  and  Reservoir  Embankments 
and   Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Water 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo. $2.50 

LESLIE. — Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thousand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  In  I2mo.,  cloth $1.50 

LIEBER. — Assayer's  Guide  : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
the  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  I2mo.  .  .  .  $1.25 

LOVE. — The  Art  of  Dyeing,  Cleaning,  Scouring,  and  Finish- 
ing, on  the  Most  Approved  English  and  French  Methods : 
Being  Practical  Instructions  in  Dyeing  Silks,  Woolens,  and  Cottons, 
Feathers,  Chips,  Straw,  etc.  Scouring  and  Cleaning  Bed  and  Win- 
dow  Curtains,  Carpets,  Rugs,  etc.  French  and  English  Cleaning, 
any  Color  or  Fabric  of  Silk,  Satin,  or  Damask.  By  THOMAS  LOVE, 
a  Working  Dyer  and  Scourer-  Second  American  Edition,  to  which 


18         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

are  added  General  Instructions  for  the  use  of  Aniline  Colors.     8vo. 

343  Pages       ,  • $5.00 

LUKIN.— Amongst  Machines; 

Embracing  Descriptions  of  the  various  Mechanical  Appliances  used- 
in  the  Manufacture  of  Wood,  Metai,  and  other  Substances.  J2mo. 

tUKIN.— The  Boy  Engineers : 
What  They  Did,  and  How  They  Did  It.     With  30  plates.    1 8mo. 

#i-75 

LUKIN.— The  Y^ung  Mechanic : 

Practical  Carpentry.  Containing  Directions  for  the  Use  of  all  kinds 
of  Tools,  and  for  Construction  of  Steam- Engines  and  Mechanical 
Models,  including  the  Art  of  Turning  in  Wood  and  Metal.  By  JOHN 
LUKIN,  Author  of  "The  Lathe  and  Its  Uses,"  etc.  Illustrated. 
I2rrio.  .  .  .  .  .  .  .  .  .  :  .  $ i. 75 

MAIN  and  BROWN. — Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And  Examination  Papers;  with  Hints  for  their  Solution.  By 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal  Naval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.  I2mo.,  cloth  .  $1.50 

MAIN  and  BROWN. — The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.  MAIN,   M.  A.  F.  R.,  Ass't   S.   Professor   Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineer 
R.  N.,  attached  to  the  R.  N.  College.     Illustrated.     8vo.  .         $1.50 

MAIN  and  BROWN.— The  Marine  Steam-Engine. 

By  THOMAS  J.  MAIN,  F.  R.  Ass't  S.  Mathematical  Professor  at  the 
Royal  Naval  College,  Portsmouth,  and  THOMAS  BROWN,  Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.  Attached  to  the  Royal  Naval 
College.  With  numerous  illustrations.  8vo.  .  .  .  $5.00 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Mechanical 

Engineers : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the  Threads 
of  Screws  of  any  Required  Pitch ;  with  a  Table  for  Making  the  Uni- 
versal Gas-Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 
8vo 50 

MICHELL.— Mine  Drainage: 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under- 
ground Steam  Pumping  Machinery.  With  a  Description  of  a  large 
number  of  the  best  known  Engines,  their  General  Utility  and  the 
Special  Sphere  of  their  Action,  the  Mode  of  their  Application,  and 
their  Merits  compared  with  other  Pumping  Machinery.  By  STEPHEN 
MICHELL.  Illustrated  by  137  engravings.  8vo.,  277  pages  .  $6.00 

MOLESWORTH.— Pocket-Book    of    Useful     Formulae     and 

Memoranda  for  Civil  and  Mechanical  Engineers. 
By  GUILFORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident   Engineer  of  the  Ceylon  Railway.     Full- 
bound  in  Pocket-book  form $i,oa 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE,          19 

MOORE.— The  Universal  Assistant  and  the  Complete  Me- 
chanic  : 

Containing  over  one  million  Industrial  Facts,  Calculations,  Receipts, 
Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
in  every  occupation,  from  the  Household  to  the  Manufactory.  By 
R.  MOORE.  Illustrated  by  500  Engravings.  I2mo.  .  $2.50 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks  : 
By  means  of  the  Prismoidal  Formula.  Illustrated  with  Numerom 
Wood-Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas. 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyors, 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork. 
By  ELWOOD  MORRIS,  C.  E.  8vo $1.50 

MORTON. — The  System  of  Calculating  Diameter,  Circumfer- 
ence, Area,  and  Squaring  the  Circle : 

Together  with  Interest  and  Miscellaneous  Tables,  and  other  informa- 
tion. By  JAMES  MORTON.  Second  Edition,  enlarged,  with  the 
Metric  System.  I2mo.  .......  $1.00 

NAPIER.— Manual  of  Electro  -  M  etallurgy : 

Including  the  Application  of  the  Art  to  Manufacturing  Processes. 
By  JAMES  NAPIER.  Fourth  American,  from  the  Fourth  London 
edition,  revised  and  enlarged.  Illustrated  by  engravings.  8vo.  $1.50 

NAPIER. — A  System  of  Chemistry  Applied  to  Dyeing. 

By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Edi- 
tion. Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar  Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus- 
trated. 8vo.  422  pages  .  $5-OO 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formulae,  for 
finding  the  Discharge  of  Water  from  Orifices,  Notches, 
Weirs,  Pipes,  and  Rivers : 

Third  Edition,  with  Additions,  consisting  of  New  Formulae  for  the 
Discharge  from  Tidal  and  Flood  Sluices  and  Siphons ;  general  infor- 
mation on  Rainfall,  Catchment-Basins,  Drainage,  Sewerage,  Water 
Supply  for  Towns  and  Mill  Power.  By  TORN  NEVILLE,  C.  E.  M  R. 
I.  A. ;  Fellow  of  the  Royal  Geological  Society  of  Ireland.  Thick 
I2mo. #3-50 

NEWBERY. — Gleanings     from     Ornamental     Art    of    every 

style : 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
1862,  and  the  best  English  and  Foreign  works.  In  a  series  of  100 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  By 
ROBERT  NEWBERY.  410. $12.50 

NICHOLLS.  -The  Theoretical  and  Practical  Boiler-Maker  and 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor. 
Foremen  and  Working  Boiler-Makers.  Iroi,  Copper,  and  Tinsmiths* 


20         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

Draughtsmen,  Engineers,  the  General  Steam-using  Public,  and  for  the 
Use  of  Science  Schools  and  Classes.  By  SAMUEL  NICHOLLS.  Illus- 
trated by  sixteen  plates,  I2mo.  .  .  ...  ..  y. .  %#&*  $2.50 

NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding : 

Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gilding,  and  Finishing.  Also,  the  Art  of  Marbling  Book-edges  and 
Paper.  By  JAMES  B.  NICHOLSON.  Illustrated.  I2mo.,  cloth  $2.25 

NICOLLS.— The  Railway  Builder: 

A  Hand-Book  for  Estimating  the  Probable  Cost  of  American  Rail- 
way Construction  and  Equipment.  By  WILLIAM  J.  NICOLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form  .-.  $2.00 

NORMANDY.— The  Commercial  Handbook  of  Chemical  An- 

alysis : 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  o? 
Commercial  Value  of  Substances  used  in  Manufactures,  in  Trades, 
and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
to  a  great  extent  rewritten.  By  HENRY  M.  NOAD,  Ph.D.,  F.R.S., 
thick  I2mo. $5.00 

NORRIS. — A  Handbook  for  Locomotive   Engineers  and  Ma- 
chinists : 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco- 
motives;  Manner  of  Setting  Valves;  Tables  cf  Squares,  Cubes,  Areas, 
etc.,  etc.  By  SEPTIMUS  NORRIS,  M.  E.  New  edition.  Illustrated, 
I2mo $1.50 

NYSTRGM. — A  New  Treatise  on  Elements  of  Mechanics  : 
Establishing  Strict  Precision  in  the   Meaning  of  Dynamical   Terms: 
accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me- 
trology.    By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo.       $2.00 

NYSTROM. — On  Technological  Education  and  the  Construc- 
tion of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  late 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi- 
tional matter.  Illustrated  by  seven  engravings.  I2mo.  .  $1.50 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 

Containing  a  brief  account  of  all  the  Substances  and  Processes  in 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  Practical 
Receipts  and  Scientific  Information.  By  CHARLES  O'NEILL,  Analy- 
tical Chemist.  To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.  By  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  8vo., 
491  pages $5-00 

ORTON. — Underground  Treasures'. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
of  all  the  Useful  Minerals  within  the  United  States.  By  JAMES 
ORTON,  A.M.,  Late  Professor  of  Natural  History  in  Vassar  College, 
K.  Y.;  Cor.  Mem.  of  the  Academy  of  Natural  Sciences,  Philadelphia, 
and  of  the  Lyceum  of  Natural  History,  New  York ;  author  of  the 
•"Andes  and  the  Amazon,"  etc.  A  New  Edition,  with  Additions. 
Illustrated $1.50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         21 


OSBORN.— The  Metallurgy  of  Iron  and  Steel: 

Theoretical  and  Practical  in  all  its  Branches;  with  special  reference 
to  American  Materials  and  Processes.  By  H.  S.  OJBORN,  LL.  D., 
Professor  of  Mining  and  Metallurgy  in  Lafayette  College,  Easton, 
Pennsylvania.  Illustrated  by  numerous  large  folding  plates  and 
wood-engravings.  8vo.  ......  $25.00 

OSBORN. — A  Practical  Manual  of  Minerals,  Mines  and  Min- 
ing : 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and  Associations  of  the  Useful  Minerals ;  their  Methods  of 
Chemical  Analysis  and  Assay :  together  with  Various  Systems  of 
Excavating  and  Timbering,  Brick  and  Masonry  Work,  during  Driv- 
ing, Lining,  Bracing  and  other  Operations,  etc.  By  Prof.  H.  S. 
OSBORN,  LL.  D.,  Author  of  the  "  Metallurgy  of  Iron  and  Steel." 
Illustrated  by  171  engravings  from  original  drawings.  8vo.  $4-5° 

OVERMAN.— The  Manufacture  of  Steel  : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware, of  Steel  and  Iron,  and  for  Men  of  Science  and  Art.  By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  Iron,"  etc.  A  new,  enlarged,  and  revised  Edition.  By 
A.  A.  FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  $1.50 

OVERMAN.— The  Moulder's  and  Founder's  Pocket  Guide  : 
A  Treatise  on  Moulding  and  Founding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow- 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues ;  Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals;  Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals  ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.  By  FREDERICK  OVERMAN,  M.  E.  A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
Ordnance,  Malleable  Iron  Castings,  etc.  By  A.  A.  FESQUET,  Chem- 
ist and  Engineer.  Illustrated  by  44  engravings.  I2mo.  .  $2.00 

PAINTER,  GILDER,  AND  VARNISHER'S  COMPANION; 
Containing  Rules  and  Regulations  in  everything  relating  to  the  AnS 
of  Painting,  Gilding,  Varnishing,  Glass- Staining,  Graining,  Marbling, 
Sign- Writing,  Gilding  on  Glass,  and  Coach  Painting  and  Varnishing; 
Tests  for  the  Detection  of  Adulterations  in  Oils,  Colors,  etc. ;  and  a 
Statement  of  the  Diseases  to  which  Painters  are  peculiarly  liable,  with 
the  Simplest  and  Best  Remedies.  Sixteenth  Edition.  Revised,  with 
an  Appendix.  Containing  Colors  and  Coloring — Theoretical  and 
Practical.  Comprising  descriptions  of  a  great  variety  of  Additional 
Pigments,  their  Qualities  and  Uses,  to  which  are  added,  Dryers,  and 
Modes  and  Oper.itions  of  Painting,  etc.  Together  with  Chevreul's 
Principles  of  Harmony  and  Contrast  of  Colors.  I2mo.  Cloth  $1.50 

PALLETT. — The  Miller's,  Millwright's,  and  Engineer's  Guide. 
By  HENRY  PALLETT.  Illustrated.  I2mo.  .  .  .  $3.00 


22         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

PERCY. — The  Manufacture  of  Russian  Sheet-Iron. 

By  JOHN  PERCY,  M.  D.,  F.  R.  S.,  Lecturer  on  Metallurgy  at  the 
Royal  School  of  Mines,  and  to  The  Advance  Class  of  Artillery 
Officers  at  the  Royal  Artillery  Institution,  Woolwich ;  Author  of 
"  Metallurgy."  With  Illustrations.  8vo.,  paper  .  .  50  cts, 

PERKINS. — Gas  and  Ventilation  : 

Practical  Treatise  on  Gas  and  Ventilation.  With  Special  Relation 
to  Illuminating,  Heating,  and  Cooking  by  Gas.  Including  Scientific 
Helps  to  Engineer-students  and  others.  With  Illustrated  Diagrams. 
By  E.  E.  PERKINS.  I2mo.,  cloth  .  .  «'•  .  .  $1.25 

JERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

and  Boiler  Plate  Roller  : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and  Piles 
to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron ;  the  Thickness  of  the  Bar  Gauge 
in  decimals ;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  1 12  Ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 
Estimated  and  collected  by  G.  H.  PERKINS  and  J.  G.  STOWE.  $2.5$ 

POWELI CHANCE— HARRIS.— The    Principles  of   Glass 

Making. 

By  HARRY  J.  POWELL,  B.  A.  Together  with  Treatises  on  Crown  and 
Sheet  Glass;  by  HENRY  CHANCE,  M.  A.  And  Plate  Glass,  by  H. 
G.  HARRIS,  Asso.  M.  Inst.  C.  E.  Illustrated  i8mo.  .  $1.50 

PROCTOR. — A  Pocket-Book  of  Useful  Tables  and  Formulae 

for  Marine  Engineers : 

By  FRANK  PROCTOR.  Second  Edition,  Revised  and  Enlarged. 
Full -bound  pocket-book  form $1.50 

REGNAULT. — Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  $7.50 

RICHARDS. — Aluminium : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illustrated  by  16  engravings.  12  mo.  346  pages  $2.50 

RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors;  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessaiy  Apparatus  and  Directions  for  its  Use ;  Dryers ;  the 
Testing,  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
RIFFAULT,  VERGNAUD,  and  TOUSSAINT.  Revised  and  Edited  by  M. 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          23 

F.  MALEPEYRE.  Translated  from  the  French,  by  A.  A.  FESQUET; 
Chemist  and  Engineer.  Illustrated  by  Eighty  engravings.  In  one 
vol.,  8vo.,  659  pages •  $/-5° 

ROPER.— A  Catechism  of  High- Pressure,  or  Non-Condensing 

Steam -Engines  : 

Including  the  Modelling,  Constructing,  and  Management  of  Steam- 
Engines  and  Steam  Boilers.  With  valuable  illustrations.  By  STE- 
PHEN ROPER,  Engineer.  Sixteenth  edition,  revised  and  enlarged. 
i8mo.,  tucks,  gilt  edge $2.00 

fcOPER. — Engineer's  Handy-Book: 

Containing  a  full  Explanation  of  the  Steam-Engine  Indicator,  and  its 
Use  and  Advantages  to  Engineers  and  Steam  Users.  With  Formulae 
for  Estimating  the  Power  of  all  Classes  of  Steam-Engines ;  also, 
Facts,  Figures,  Questions,  and  Tables  for  Engineers  who  wish  to 
qualify  themselves  for  the  United  States  Navy,  the  Revenue  Service, 
the  Mercantile  Marine,  or  to  take  charge  of  the  Better  Class  of  Sta- 
tionary Steam-Engines.  Sixth  edition.  i6mo..  690  pages,  tucks, 
gilt  edge #3.50 

ROPER. — Hand-Book  of  Land  and  Marine  Engines  : 

Including  the  Modelling,  Construction,  Running,  and  Management 
of  Lane3  and  Marine  Engines  and  Boilers.  With  illustrations.  By 
STEPHEN  ROPER,  Engineer.  Sixth  edition.  I2mo.,t\'cks,  gilt  edge. 

#3-50 
ROPER.— Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion, Management,  and  Running  of  Locomotives.  By  STEPHEN 
ROPER.  Eleventh  edition.  i8mo.,  tucks,  gilt  edge  .  $2.50 

ROPER.— Hand-Book  of  Modern  Steam  Fire-Engines. 

With  illustrations.  By  STEPHEN  ROPER,  Engineer.  Fourth  edition, 
I2mo.,  tucks,  gilt  edge  .......  $3-$O 

ROPER. — Questions  and  Answers  for  Engineers. 

This  little  book  contains  all  the  Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or 
dinary  intelligence  may  commit  them  to  memory  in  a  short  time.  By 
STEPHEN  ROPER,  Engineer.  Third  edition  .  .  .  $3.00 

ROPER. — Use  and  Abuse  of  the  Steam  Boiler. 
By  STEPHEN  ROPER,  Engineer.     Eighth  edition,  with  illustrations. 
i8mo.,  tucks,  gilt  edge $2.00 

ROSE. — The  Complete  Practical  Machinist : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools, 
Tool  Grinding,  Marking  out  Work,  etc.  By  JOSHUA  ROSE.  Illus- 
trated by  356  engravings.  Thirteenth  edition,  thoroughly  revised 
and  in  great  part  rewritten.  In  one  vol.,  I2mo.,  439  pages  $2.50 

ROSE. — Mechanical  Drawing  Self-Taught: 
Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Instruments,  Elementary  Instruction  in  Practical  Mechanical  Draw 


24         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

ing,  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
Motions,  Engines  and  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  330  engravings.  8vo.,  313  pages  ....  $4.00 

ROSE. — The  Slide- Valve  Practically  Explained: 

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JOSHUA  ROSE,  M.  E.  Illustrated  by  35  engravings  .  $1.00 

ROSS. — The  Blowpipe  in  Chemistry,  Mineralogy  and  Geology : 
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ing Examples,  and  Instructions  for  Making  Apparatus.  By  LIEUT.- 
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I2mo -  ....  .  $1.50 

SHAW.— Civil  Architecture : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building,  con- 
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Architect.  To  which  is  added  a  Treatise  on  Gothic  Architecture,  etc. 
By  THOMAS  W.  SILLOWAY  and  GEORGE  M.  HARDING,  Architects. 
The  whole  illustrated  by  102  quarto  plates  finely  engraved  on  copper. 
Eleventh  edition.  4to.  .......  $10.00 

SHUNK. — A  Practical  Treatise  on  Railway  Curves  and  Loca- 
tion, for  Young  Engineers. 
By  W.  F.  SHUNK,  C.  E.    121110.    Full  bound  pocket-book  form  $2.00 

SLATER. — The  Manual  of  Colors  and  Dye  Wares. 
By  J.  W.  SLATER.     I2mo $3-75 

SLOAN. — American  Houses  : 

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SLOAN. — Homestead  Architecture: 

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SLOANE. — Home  Experiments  in  Science. 

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SMITH. — A  Manual  of  Political  Economy. 

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Index.  I2mo $1.25 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         25 

SMITH. — Parks  and  Pleasure- Grounds : 

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Gardens.  By  CHARLES  H.  J.  SMITH,  Landscape  Gardener  and 
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SMITH.— The  Dyer's  Instructor  : 

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the  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs,  and  the 
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SMYTH. — A  Rudimentary  Treatise  on  Coal  and  Coal-Mining. 
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SNIVELY. — A  Treatise  on  the  Manufacture  of  Perfumes  and 

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SNIVELY. — Tables  for  Systematic  Qualitative  Chemical  Anal- 
ysis. 
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SNIVELY.— The  Elements  of  Systematic  Qualitative  Chemical 

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#2.00 

STEWART. — The  American  System  : 

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STOKES. — The  Cabinet  Maker  and  Upholsterer's  Companion: 
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ing Wood,  Ivory,  Bone,  Tortoise-Shell,  etc.  Directions  for  Lacker- 
ing, Japanning,  and  Varnishing;  to  make  French  Polish,  Glues, 
Cements,  and  Compositions;  with  numerous  Receipts,  useful  to  work- 
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STRENGTH  AND  OTHER  PROPERTIES  OF  METALS; 
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SULLIVAN. — Protection  to  Native  Industry. 

By  Sir  EDWARD  SULLIVAN,  Baronet,  author  of  "  Ten  Chapters  on 
Social  Reforms."  8vo #1.50 


*6         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

SYME. — Outlines  of  an  Industrial  Science. 

By  DAVID  SYME.     I2mo.          .        f"  .        »        .        $2.00 

TABLES      SHOWING     THE     WEIGHT     OF     ROUND, 
SQUARE,  AND  FLAT  BAR  IRON,  STEEL,  ETC., 

By  Measurement.     Cloth  *         «    ;     .         .         .         .  63 

TAYLOR.— Statistics  of  Coal : 

Including  Mineral  Bituminous  Substances  employed  in  Arts  and 
Manufactures;  with  their  Geographical,  Geological,  and  Commercial 
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facture. By  R.  C.  TAYLOR.  Second  edition,  revised  by  S.  S.  HALDE- 
MAN.  Illustrated  by  five  Maps  and  many  wood  engravings.  8vo., 
cloth $10.00 

TEMPLETON. — The  Practical  Examinator  on  Steam  and  the 

Steam -Engine: 

With  Instructive  References  relative  thereto,  arranged  for  the  Use  of 
Engineers,  Students,  and  others.  By  WILLIAM  TEMPLETON,  En- 
gineer.  I2mo. .$1.25 

THAUSING. — The  Theory  and  Practice  of  the  Preparation  of 

Malt  and  the  Fabrication  of  Beer: 

With  especial  reference  to  the  Vienna  Process  of  Brewing.  Elab- 
orated from  personal  experience  by  JULIUS  E.  THAUSING,  Professor 
at  the  School  for  Brewers,  and  at  the  Agricultural  Institute,  Modling, 
near  Vienna.  Translated  from  the  German  by  WILLIAM  T.  BRANNT, 
Thoroughly  and  elaborately  edited,  with  much  American  matter,  and 
according  to  the  latest  and  most  Scientific  Practice,  by  A.  SCHWARZ 
and  DR.  A.  H.  BAUER.  Illustrated  by  140  Engravings.  8vo.,  815 
pages $10.00 

THOMAS. — The  Modern  Practice  of  Photography: 
By  R.  W.  THOMAS,  F.  C.  S.    8vo.  ....  75 

THOMPSON.— Political  Economy.     With  Especial  Reference 

to  the  Industrial  History  of  Nations  : 

By  ROBERT  E.  THOMPSON,  M.  A.,  Professor  of  Social  Science  in  the 
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TURNER'S  (THE)  COMPANION: 

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TURNING  :   Specimens  of  Fancy  Turning  Executed  on  the 

Hand  or  Foot- Lathe  : 

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Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Photographs. 
4to. $3.00 

URBIN— BRULL.— A  Practical  Guide  for  Puddling  Iron  and 

Steel. 
By  ED.  URBIN,  Engineer  of  Arts  and  Manufactures.     A  Prize  Essay, 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  27 

read  before  the  Association  of  Engineers,  Graduate  of  the  School  of 
Mines,  of  Liege,  Belgium,  at  the  Meeting  of  1865-6.  To  which  is 
added  A  COMPARISON  OF  THE  RESISTING  PROPERTIES  OF  IRON  AND 
STEEL.  By  A.  BRULL.  Translated  from  the  French  by  A.  A.  FES- 
QUET,  Chemist  and  Engineer.  8vo.  ....  $1.00 

VAILE. — Galvanized- Iron  Cornice-Worker's  Manual: 
Containing  Instructions  in  Laying  out  the  Different  Mitres,  and 
Making  Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also, 
Tables  of  Weights,  Areas  and  Circumferences  of  Circles,  and  other 
Matter  calculated  to  Benefit  the  Trade.  By  CHARLES  A.  VAILE. 
Illustrated  by  twenty-one  plates.  410 $5-OO 

VILLE. — On  Artificial  Manures  : 

Their  Chemical  Selection  and  Scientific  Application  to  Agriculture. 
A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VILLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 
engravings.  8vo.,  450  pages $6.00 

VILLE.— The  School  of  Chemical  Manures  : 
Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.     From 
the  French  of  M.  GEO.  VILLE,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer.    With  Illustrations.     I2mo.  ....         $1.25 

VOGDES. — The  Architect's  and  Builder's  Pocket  -Companion 

and  Price-Book : 

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Measures,   Sizes,   Weights,   Strengths,   etc.,   of  Iron,   Wood,  Stone, 
Brick,  Cement  and  Concretes,  Quantities  of  Materials  in  given  Sizes 
and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
Bilis  of  Prices  for  Carpenter's  Work  and  Painting ;  also,  Rules  for 
Computing  and  Valuing  Brick  and  Brick  Work,  Stone  Work,  Paint- 
ing,  Plastering,  with   a   Vocabulary  of  Technical   Terms,  etc.     By 
FRANK  W.  VOGDES,  Architect,  Indianapolis,  Ind.    Enlarged,  revised, 
and  corrected.     In  one  volume,  368  pages,  full-bound,  pocket-book 
form,  gilt  edges          ........         $2.00 

Cloth         .  1.50 

WAHL. — Galvanoplastic  Manipulations  : 

A  Practical  Guide  lor  the  Gold  and  Silver  Electroplater  and  the  Gal- 
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Metals  by  means  of  the  Battery  and  the  Dynamo-Electric  Machine, 
as  well  as  the  most  approved  Processes  of  Deposition  by  Simple  Im- 
mersion, with  Descriptions  of  Apparatus,  Chemical  Products  employed 
in  the  Art,  etc.  Based  largely  on  the  "  Manipulations  Hydroplas- 
tiques"  of  ALFRED  ROSELEUR.  By  WILLIAM  H.  WAHL,  Ph.  D. 
(Heid),  Secretary  of  the  Franklin  Institute.  Illustrated  by  189  en- 
gravings. 8vo.,  656  pages $7-$o 

WALTON.— Coal-Mining  Described  and  Illustrated: 
TBy  THOMAS  H.  WALTON,  Mining  Engineer.     Illustrated  by  24  large 
and  elaborate  Plates,  after  Actual  Workings  and  Apparatus.  $5.00 


28         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

WARE.— The  Sugar  Beet. 

\  Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varieties 
of  the  Sugar  Beet,  Examination,  Soils,  Tillage,  Seeds  and  Sowing, 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserva- 
tion, Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWIS 
S.  WARE,  C.  E.,  M.  E.  Illustrated  by  ninety  engravings.  8vo. 

$4.00 

WARN.— The  Sheet-Metal  Worker's  Instructor: 
For  Zinc,  Sheet- Iron,  Copper,  and  Tin- Plate  Workers,  etc.  Contain- 
ing a  selection  of  Geometrical  Problems ;  also,  Practical  and  Simple 
Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin-Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty- 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  .  $3.00 

WARNER. — New  Theorems,  Tables,  and  Diagrams,  for  the 
Computation  of  Earth-work : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates, 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profes- 
sional Computers.  In  two  parts,  with  an  Appendix.  Part  I.  A  Prac- 
tical Treatise ;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix. 
Containing  Notes  to  the  Rules  and  Examples  of  Part  I.;  Explana- 
tions of  the  Construction  of  Scales,  Tables,  and  Diagrams,  and  a 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights. 
The  whole  illustrated  by  numerous  original  engravings,  comprising 
explanatory  cuts  for  Definitions  and  Problems,  Stereometric  Scales 
and  Diagrams,  and  a  series  of  Lithographic  Drawings  from  Models : 
Showing  all  the  Combinations  of  Solid  Forms  which  occur  in  Railroad 
Excavations  and  Embankments.  By  JOHN  WARNER,  A.  M.,  Mining 
and  Mechanical  Engineer.  Illustrated  by  14  Plates.  A  new,  revised 
and  improved  edition.  8vo.  .  .  .  ...  $4.00 

WATSON.— A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds, 
Ivory,  Bone  and  Precious  Woods;  Dyeing,  Coloring,  and  French 
Polishing;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  By 
EGBERT  P.  WATSON,  Author  of  "  The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON. — The  Modern  Practice  of  American  Machinists  and 
Engineers  : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow-work  generally, with 
the  most  Economical  Speed  for  the  same  ;  the  Results  verified  by 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  Floor.  Togethei 


HLNRV  CAREY  BAIRD  &  CO.'S  CATALOGUE.          29 

with  Workshop  Management,  Economy  of  Manufacture,  the  Steam 
Engine,  Boiltrs,  Gears,  Belling,  etc.,  etc.  By  EGBERT  P.  WATSON. 
Illustrated  by  eighty-six  engravings.  I2mo.  .  .  .  $2.50 

*VATSON. — The  Theory  and  Practice  of  the  Art  of  Weaving 

by  Hand  and  Power  : 

With  Calculations  and  Tables  for  the  Use  of  those  connected  with  the 
Trade.  By  JOHN  WATSON,  Manufacturer  and  Practical  Machine- 
Maker.  Illustrated  by  large  Drawings  of  the  best  Power  Looms. 
8vo.  .  $7.50 

WATT.— The  Art  of  Soap  Making : 

A  Practical  Hand-book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.,  including  many  New  Processes,  and  a  Chapter  on 
the  Recovery  of  Glycerine  from  Waste  Leys.  By  ALEXANDER 
WATT.  111.  I2mo $3-oo 

WEATHERLY. — Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
tallizing, Lozenge-making,  Comfits,  Gum  Goods, 
And  other  processes  for  Confectionery,  etc.,  in  which  are  explained, 
in  an  easy  and  familiar  manner,  the  various  Methods  of  Manufactur- 
ing every  Description  of  Raw  and  Refined  Sugar  Goods,  as  sold  by 
Confectioners  and  others.  I2mo $1-5° 

WEDDING.— Elements  of  the  Metallurgy  of  Iron. 
By  Dr.  HERMANN  WEDDING,  Royal  Privy  Counsellor  of  Mines,  Ber- 
lin, Prussia.  Translated  from  the  second  revised  and  rewritten  Ger- 
man edition.  By  WILLIAM  T.  BRANNT,  Graduate  of  the  Royal  Ag- 
ricultural College  at  Eldena,  Prussia.  Edited  by  WILLIAM  H. 
WAHL,  Ph.  D.,  Secretary  of  the  Franklin  Institute,  Philadelphia. 
Illustrated  by  about  250  engravings.  8vo.,  about  500  pages  (In  prep- 
aration.} ......... 

WEINHOLD. — Introduction  to  Experimental  Physics,  Theo- 
retical and  Practical. 

Including  directions  for  Constructing  Physical  Apparatus  and  for 
Making  Experiments.  By  ADOLF  F.  WEINHOLD,  Professor  in  the 
Royal  Technical  School  at  Chemnitz.  Translated  and  edited,  with 
the  author's  sanction,  by  BENJAMIN  LOEWY,  F.  R.  A.  S.,  with  a 
preface,  by  G.  C.  FOSTER,  F.  R.  S.  Illustrated  by  three  colored  plates 
and  404  wood-cuts.  8vo.,  848  pages  .... 

WIGHTWICK.— Hints  to  Young  Architects : 

Comprising  Advice  to  those  who,  while  yet  at  school,  are  destined 
to  the  Profession;  to  such  as,  having  passed  their  pupilage,  are  about 
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about  to  practise.  Together  with  a  Model  Specification  involving  a 
great  variety  of  instructive  and  suggestive  matter.  By  GEORGB 
WIGHTWICK,  Architect.  A  new  edition,  revised  and  considerably 
enlarged ;  comprising  Treatises  on  the  Principles  of  Construction 
and  Design.  By  G.  HUSKISSON  GUILLAUME,  Architect.  Numerous 
Illustrations.  One  vol.  I2mo $2.OO 

WILL. — Tables  of  Qualitative  Chemical  Analysis. 
With  an  Introductory  Chapter  on  the  Course  of  Analysis.     By  Pro- 
essor  HEINRICH  WILL,  of  Giessen,  Germany.     Third  American. 


^o          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

from  the  eleventh  German  edition.     Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle,  Pa. 
8vo.  .         .         •         .         .         .        ...        .11.50 

WILLIAMS.— On  Heat  and  Steam  : 

Embracing  New  Views  of  Vaporization,  Condensation,  and  Explo- 
sion. By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated  8vo. 

#350 

WILSON. — A  Treatise  on  Steam  Boilers  : 

Their  Strength,  Construction,  and  Economical  Working.  By  ROBERT 
WILSON.  Illustrated  I2mo $2.50 

WILSON.— First  Principles  of  Political  Economy : 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization. 
By  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo.  .  $1.50 

WOHLER.— A  Hand-book  of  Mineral  Analysis. 
By  F.  WQHLER,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen.     Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer    Polytechnic    Institute,   Troy,    New    York.      Illustrated 
I2mo .         .         .         .         «       •  $3.00 

WORSSAM.— On  Mechanical  Saws : 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  .  $2.50 


RECENT  ADDITIONS. 

ANDERSON— The  Prospector's  Hand-Book : 

A  Guide  for  the  Prospector  and  Traveler  in  Search  of  Metal  Bearing 
or  other  Valuable  Minerals.  By  J.  W.  ANDERSON.  52  Illustrations. 
I2mo #1.50 

BILGRAM.— Slide-Valve  Gears  : 

A  new,  graphical  method  for  Analyzing  the  Action  of  Slide-Valves, 
moved  by  Eccentrics,  Link  Motions,  and  Cut-off  Gears,  offering  easy 
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